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HOMEBREW Digest #4428
HOMEBREW Digest #4428 Wed 17 December 2003
FORUM ON BEER, HOMEBREWING, AND RELATED ISSUES
Digest Janitor: janitor@hbd.org
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Contents:
Scorched a direct fired mash ("Urban, Michael J, WCITS")
Re: How to throttle magnetic pump? ("Gary Smith")
beer in Freiburg & Nurnberg (Germany) ("Peter A. Ensminger")
er: Pediococcus ("-S")
Re: RIMS temperature control ("Gary Smith")
Beersicle ("Dave Larsen")
re: RIMS Temperature Control ("-S")
RE: RIMS temperature control (Steve Jones)
Re: Rogue Chocolate Stout (R.A.)" <rbarrett@ford.com>
Karlsruhe (Jim Busch)
PID Control ("Todd M. Snyder")
re: Transporting Kegged Beer ("C.D. Pritchard")
Yeast Cannibalism? ("Gregory D. Morris")
re: How to throttle magnetic pump? ("C.D. Pritchard")
RE: Throttling Outflow of Magnetic Pump ("Parker Dutro")
Beer on a German Tour ("Bob Speights")
RIMS thermal density ("Chad Stevens")
5 gallons per minute ("Ronald La Borde")
Re: PID Control ("Mike Sharp")
natural chocolate flavoring (Marc Sedam)
creating clear canned wort ("Rob Dewhirst")
Re: How to throttle magnetic pump? ("David")
Re: RIMS Temperature Control (David Towson)
Re: RIMS Ramp Rates, PID Controlled etc (Dion Hollenbeck)
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Date: Mon, 15 Dec 2003 19:07:24 -0500
From: "Urban, Michael J, WCITS" <mjurban at att.com>
Subject: Scorched a direct fired mash
Beer Geeks -
My brewing partner and I just finished our first all grain brew.
Everything went well, except we managed to scorch the bottom
of our mash tun adding direct heat for the temperature steps.
The end effect on the flavor is yet to be determined, although the
wort tasted pretty darn good. I've since done some searching in the
archives, and the good news is that at least we're not alone, as
this seems to be a fairly common problem with direct fired mash
tuns. The bad news is that I didn't find a silver bullet; there wasn't
any secret which would allow us to avoid the same situation in
the future. The solution seems to be to find a way to avoid direct
heat in the mash steps.
I've since given some thought to the alternatives. Playing around
with Promash tells me I can do all the steps with infusions if I
dough in with a stiff mash (~.75 qt./lb.), and use infusion temps
of 210 oF. Since the mash tun is not insulated (yet), we may
have to add small amounts of direct heat to maintain temp, but
the ramps I think we can handle with infusions, and still end up
with a final ration of ~1.85 qts./lb.
So after all this rambling, here's the question: Are we in danger
of local enzyme denaturing by adding water at 210 oF.? I know
we'll have to be stirring pretty vigorously, but still the temp
gradient is going to be pronounced until everything stabilizes.
Also, is there any advantage (or disadvantage) to adding the
infusion through the outlet, thus introducing the water at the
bottom of the mash rather than the top. Since heat rises, I
thought it might be better to reach a stable temp that way,
and also to avoid any cooling at the surface.
Advice would be appreciated.
Michael Urban
Winter Springs, FL
[952.4, 170.5]
------------------------------
Date: Tue, 16 Dec 2003 00:58:46 -0600
From: "Gary Smith" <mandolinist at ameritech.net>
Subject: Re: How to throttle magnetic pump?
Brendan asks how to get or not to get pumped up
> I've got a new magnetic pump (from morebeer.com) and was wondering if
> the best way to throttle the flow is to (1) restrict flow output or
> (2) use a dimmer switch to reduce power to motor. I understand that
> reducing motor speed would also slow the cooling fan, but I guess I
> could cool externally. Does outflow restriction have any negative
> impact on pump/motor? Thanks in advance.
With a magnetic pump you want to throttle the output. If you throttle the
input you can cause cavitation (spinning in place) and this will cause
bubbling which will severely affect the pumping. At high enough temps
maybe even a problem with hot side aeration.
With peristaltic pumps you must throttle the intake side for with an
obstructon on the output you will end up with a burst output line.
Gary
Gary Smith
CQ DX de KA1J
http://musician.dyndns.org
Most of us know how to say nothing--few of us know when.
------------------------------
Date: Tue, 16 Dec 2003 02:21:25 -0500
From: "Peter A. Ensminger" <ensmingr at twcny.rr.com>
Subject: beer in Freiburg & Nurnberg (Germany)
Hi Stan,
I lived in Freiburg from 1989-1991 and visited again in 1996.
Hausbrauerei Feierling, <http://www.inselbrauerei.de/>, was great back
then. Now? There's also Martin's Brau (another Hausbrauerei). Their beer
was less impressive, but their menu was better.
My memories of Nurnburg are a bit fuzzy, but this region is known for
its "smoke beer". I would also suggest a visit to the
Weizenbeerglasmuseum
<http://museumsvielfalt-nuernberg.de/weizenbierglasmuseum/> in Nurnberg.
Cheerio!
Peter A. Ensminger
Syracuse, NY
- -----
I have very limited internet access right now, so I haven't been able to
check the archives. Sorry.
Soon I'll be driving from Prague to Nurnberg (spending a couple of nights)
and then to Freiburg (extreme western Germany, very close to French
border)--I'm picking up my nephew who lives with his mother in Freiburg
and bringing him back to Tabor for the holidays with his father.
Any recommendations for beer drinking along this route?
Thanks!
Stan Burnett
Tabor, CZ
------------------------------
Date: Tue, 16 Dec 2003 02:33:54 -0500
From: "-S" <-s at adelphia.net>
Subject: er: Pediococcus
A.J deLange writes ...
>The aptly named P. damnosus is easily recognized under the microscope.
>It looks like pairs or quads of little dots.
But so do all Pedios ! Aerococci, Amaricocci are tetrad formers as well and
it's likely some other lactos are.. Sarcina form 2x2x2 cubes which can be
difficult to distinguish. Further the list of Pedios include ... P.
claussen, P. acidilactici, P. claussenii, P. damnosus, P. dextrinicus, P.
halophilus, P. inopinatus, P. parvulus, P. pentosaceus and P. urinaeequi -
all tetrad formers and several known brewery infections among these.
Practically it doesn't matter, but they can't be identified accurately
without a sequence of distinguishing tests or by genetic or antigen means.
-S
------------------------------
Date: Tue, 16 Dec 2003 02:06:06 -0600
From: "Gary Smith" <mandolinist at ameritech.net>
Subject: Re: RIMS temperature control
On 16 Dec 2003 at 1:35, post at hbd.org wrote:
Todd wants to know about RIMS flow rates
> But 5 gpm seems really really high to me. How can you
> get that much
> flow thru the grainbed without compressing it? What
> flowrate do
> other RIMSers use?
>
> Gary says that the flow is higher than 0.25-0.5 gpm, but
> gives no
> number for what he uses, can you post your RIMS
> flowrate, Gary? I
> also agree with Gary about the carmelization myth.
> After making
> maple
I thought I'd mentioned my flow rate and looking back I
did use it in an example but didn't specify it as being my
existing rate. My rate is similar to Dion's and is also at
around five gallons per minute. I have yet to have a
stuck mash even once (lucky? Maybe...) I do start
off with the output at zero and over the space of a
minute open it fully and never slow that down throughout
the cycles.
I have a Sanke mash-tun and a SABCO false bottom
and the grain at the end of mashing is 8" from the top of
the Mash-Tun so it is a very full bed of grain I'm mashing
through.
My last wheat beer had a grain bill of 23 pounds and
of that 13 was wheat. That's more than 50% wheat
and I had a beautiful flow. Not stirring has certain
advantages and the wheat did not turn to chewing
gum in the least nor did it cause any compaction whatsoever.
I haven't actually timed it with a stopwatch but to fill my boil
kettle from the mash tun when I don't sparge takes certainly
takes no more than three minutes. All the sanke's are on the
same single tier and the boil kettle is filling through the siphon
at the bottom of the keg & going through the ball valve so it's
pumping against the increasing weight of the boil kettle mash.
With the RIMS, the flow is not against the back-pressure of
the liquid, it schleps in through the top of the mash-tun with
no added pressure to slow it down. I use two pumps in my
system but both are identical in flow rates.
I mention this to give you a real time example of the rate of
flow.
Bill at what was Moving Brews insisted I put the thermocouple
as close to the the heater output as possible and indeed my
probe tip is less than 2" from the proximal end of the heating
element. Since the controler is set to turn off at the set temp
and as the heat is not on steadily as the temperature
approaches the set point, there is no overshoot of
temperature. (Within five degrees or so of the set-point the
controler pulses on & off with more off the closer to set point
until it is 100% off at set point) below that temp the controler
is essentially 100% on.
As my entire mash-tun (top, bottom & sides), rims chamber
and connecting hoses are insulated with double layers of
metalized bubble wrap or cell foam on the hoses, it is
extremely efficient. I can put my hand anywhere on the mash
tun when it's at 170F and it is only mildly warm to the touch.
The controler does not turn on very often once the set temp
has been achieved. Overshooting the temperature can
not happen if you have your rims set up this way.
Cheers,
------------------------------
Date: Tue, 16 Dec 2003 09:10:45 +0000
From: "Dave Larsen" <hunahpumonkey at hotmail.com>
Subject: Beersicle
So I'm trying my first lager: a Marzen. I'm lagering it in my serving
fridge in a corny. In the keg right next to it is the last gallon of a
California Common I was saving for a small competition in a month or so.
After a couple months of lagering I decided the rack the Marzen and put it
on the gas to carbonate. All went very well -- well except for one thing.
For some reason I tapped on the California Common only to find out that it
was frozen solid. Imagine that, two kegs of beer side by side, one
completely frozen, the other not. I'm guessing that it has been frozen the
whole time I've been lagering the Marzen. It must have been at exactly the
right temp in relation to the respective alcohol contents to do that. The
temp on the thermometer I have in the fridge read 31 degrees F the whole
time. I've since raised it to about 35 degrees F.
So now comes the big question. Can I just thaw it out? Will it be okay?
If the temp is now 35, I guess it will thaw eventually. However, should I
let it sit out at room temp or even bathe the keg in warm water? It was a
kick ass California Common at one point. I hope I did not ruin it. I also
hope it did not ruin the keg it is sitting in, though it seems to have the
same basic shape it started with.
Dave
Tucson, AZ
------------------------------
Date: Tue, 16 Dec 2003 04:20:49 -0500
From: "-S" <-s at adelphia.net>
Subject: re: RIMS Temperature Control
Gary Smith responds to ...
>> Temperature changes on the
>> order of 1-2 degree F/min result in a ramp between
>> steps taking almost as long as the targeted rests!
>This is debatable.
I agree but guys like Ludwig Narziss recognize this ramp rate as a serious
problem over the protease range. The argument can't be ignored.
>Too fast a temperature rise will
>caramelize the sugars.
Not generally true. The caramelization is due to localized high temps. As
many have noted lower density (larger surface area) heaters and more flow
solve this problem. Easier said than done.
====
Dave Towsend, correctly IMO, posits that mash accuracy below a couple
degrees F is unnecessary. Then asks ...
>So why is a
>sudden jump in temperature needed for a multi-temperature mash?
Because all modern malt is very well modified and most malts cannot stand
much of a rest in the 50C-60C range(122F-140F) without losing foam and
mouthfeel. If you mash-in low you must find a way to boost through this
range relatively fast.
If you examine G.Fix AoBT pp29 mash schedule you'll see his boost is
essentially instantaneous from 40C to 60C - probably a boiling water bolus.
Kunze suggests decocting with a mash-in at 62C/143F to avoid this problem.
Like Ron LaBorde I feel HERMS is inherently more robust in this respect,
tho' more difficult to automate..
==
Most of the comments posted on enzymes are along the right lines. I
disagree with some fine points in DionH's comments implying saccharification
won't occur below gelatinization temps. Malt has considerable cold-water
extract(CWE), releasing on the order of 25% of the available extract in
cold water. So yes - some fractional part of the saccharification will
occur at 122F. The other 3/4ths will await gelatinization as Dion writes.
Malt gelatinization temps is in the mid-140sF, a bit higher than Dion
suggests. Yes to prevent high attenuation levels you should bounce over
this range and at least to the high 150sF rapidly.
My *opinion* is that for HBers that a protease/peptidase rests with all malt
grists must be limited to the absolute minimum necessary to prevent haze.
That may mean a short rest in the high 130sF or a mash-in as high as 143F
and thus a low saccharification rest w/ some protease activity.
After a protease rest the *only* concern a brewer should have is to choose
rests to favor or disfavor beta-amylase so to achieve the right level of
attenuation. No commercial malt will ever leave starch after even a few
minutes at mashout temperatures. It's extremely difficult to mistreat an
all-malt mash so badly that it leaves starch. Mash-in temps even at 180F
and a bit more will not leave starch.
In short conversion is almost certain, focus on haze reduction and correct
attenuation to style as the parameters to control by mash schedule.
Brewing with large amounts of starch or raw grains will change this.
-S
------------------------------
Date: Tue, 16 Dec 2003 08:15:03 -0500
From: Steve Jones <stjones1 at chartertn.net>
Subject: RE: RIMS temperature control
Todd Snyder posts in HBD 4427:
>> You use 1.5F/min. So to go from 122 to 154 took 48
>> minutes. Then you hold it at 154 for 60 minutes.
Now why did they put that damn * key right next to the /
key? It's too easy to hit the wrong one!!
It's 1.5 degrees per minute, not 1.5 minutes per degree.
Ramping up 32 degrees at 1.5 degrees per minute will take
21.33 minutes, not 48.
Steve Jones, Johnson City, TN
State of Franklin Homebrewers (http://hbd.org/franklin)
[421.8 mi, 168.5 deg] AR
------------------------------
Date: Tue, 16 Dec 2003 08:17:53 -0500
From: "Barrett, Bob (R.A.)" <rbarrett at ford.com>
Subject: Re: Rogue Chocolate Stout
There have been a few postings about Rogue's Chocolate Stout.
In the latest Rogue eNews they mention how this beer is made:
"Chocolate Stout uses Shakespeare Stout as the base, infused
with the essence of Dutch bittersweet chocolate."
Doug Hurst posted the ingredients that appear on the bottle, but
did not include the yeast. Rogue uses their "Pac Man" yeast.
It starts at 15 Plato and finishes at about 3.5 Plato.
We make the beer we drink!!
Bob Barrett
Ann Arbor, MI
(2.8, 103.6) Rennerian. Jeff was at the meeting on Friday
but not Pat!!!
------------------------------
Date: Tue, Dec 16 2003 9:18:11 GMT-0500
From: Jim Busch <jim at victorybeer.com>
Subject: Karlsruhe
When in this area of Germany, I always make a stop
at the Hausbrauerei Vogel, either in Karlsruhe or
its more suburban cousin Ettlingen. Here you will
find one of the worlds most amazing unfiltered
hefetrub Pils. Pick up a set of the nice schnapps
glasses too. www.vogelbraeu.de
When in Nurnberg, go directly north to Bamberg! Stop
at any of the numerous small breweries throughout
Franconia. Kloster Weissenohe is a favorite of mine.
Prost!
Jim Busch
------------------------------
Date: Tue, 16 Dec 2003 09:29:48 -0500
From: "Todd M. Snyder" <tmsnyder at buffalo.edu>
Subject: PID Control
Mike Sharp writes:
"The maximum ramping rate has nothing whatsoever to do with the type of
control--it's the amount of power you apply to the heating chamber. "
I agree completely. But if you have a low flowrate of wort and you set the
heating chamber at the mash target temperature, it will take a long time to
heat the _mash_ up to the target temperature.
My point is that if you could heat the recirculating wort _above_ the target
temperature to some safe but elevated temperature, you could get the heat
into the mash faster and in something more closely resembling a step instead
of a ramp.
For example, lets say you want the mash to be raised to 154F and that you
don't want the heating chamber outlet to exceed 160F. A PC based controller
could add the heat as fast as possible without exceeding the 160 limit.
When the heater has been 'on' the total number of seconds needed to add the
required heat, the software stops adding heat even though the target
temperature may not have shown up at any of the sensors.
A PID is not smart enough to dump the heat in all at once. It 'sneaks up'
on the solution with time when the temp sensor is installed on the outlet of
the heating chamber.
Then Mike missed the point about the scenario involving the probe somewhere
in the mash, which _will_ cause a time delay in the control system.
"If you're measuring the temperature at the exit of the
heating chamber, the time delay is minor. "
I agree completely, using a PID with the probe at the outlet at the heating
chamber is a perfect application for a PID. Putting the probe in the mash
or at the mash outlet is not.
Putting the probe somewhere in the mash or at the mash outlet is a recipe
for two problems. 1. Overheating the wort in the heating chamber because
the controller is not 'seeing' what it's heating 2. Because of the time
delay between applying the heat and seeing the temperature change:
overshooting the temp in the mash and at the mash outlet.
Todd Snyder
Buffalo, NY
------------------------------
Date: Wed, 24 Dec 2003 09:08:34
From: "C.D. Pritchard" <cdp at chattanooga.net>
Subject: re: Transporting Kegged Beer
Bob Hall asked for comments on favorite methods of moving kegged beer to
parties, vacations, etc.
I just strap them to a cheap moving dolly to move them but have thought
about using a backpacking frame. To ensure clear brew, I always cold
condition the secondary fermenter (a keg) then rack to a dispensing keg.
This ensures any chill haze will form/settle and remain in the secondary.
Keeping kegs cool is usually more of a problem than moving them....
For short term, I made a snug insulated sleeve that slips over a 5 gal.
cornie. It's just 3 layers of blue foam sleeping bag pad material and an
outer covering of aluminum faced bubble wrap. The first layer of pad is 1"
taller than the other two- a couple of turns of rope secures it to the keg.
Kept 5 gal. of ale drinkable for about 5 hours on a 90+ degF day. When
used at room temp, I couldn't detect any temp. rise in the brew after 6
hours.
For longer term dispensing from a cornie, I use a modified Rubbermaid 5
gal. round water cooler. With it's lid removed, a sleeve made like the
above with 3 layers of sleeping bag pads was taped atop it and the entire
thing (including bottom) was covered with aluminum faced bubble wrap. The
wrap extends ~12" above the top sleeve. A Styrofoam lid with a slot for
passage of the beer and co2 lines fits inside the outer wrap and atop the
layers of pad and keg. The exceess bubble wrap at the top is gathered and
tied to completely seal the affair. It also prevents the keg from floating
upwards in the ice/water as it's drained. it uses very little ice- one
filling (less than 7#) of ice lasted for 12 hours on a 90+ degF day
followed by another 12 hours inside at ~70 degF- and there was still ice
inside the thing.
For smaller volumes, minikegs made from 3 and 5 liter PET bottles are the
best IMHO. They are much easier to transport than a 5 gal. keg and will
fit into a fridge at the destination. Details on them are via the URL
below. I used to counterpressure fill them from a cornie but have
discovered it's not needed. Purge 'em with co2, fill from cornie using a
length of vinyl tubing attached to a cobra tap, put on tapping cap, connect
to co2 and further purge a bit with the tap cap cracked open a bit then
top-up the co2.
For co2 while away from home, I use one of the tire inflator type co2
thingees. The cartridges are expensive but they are damn handy- especially
relative to myonly other source- a 20# co2 cylinder. One useful addition
is to splice in a pressure gauge and put a "red line" indication on it at
the correct dispensing pressure- especially if others will be using the
inflator.
c.d. pritchard cdp at chattanooga.net
http://chattanooga.net/~cdp/
------------------------------
Date: Tue, 16 Dec 2003 09:37:31 -0500 (EST)
From: "Gregory D. Morris" <gmorris at literati.com>
Subject: Yeast Cannibalism?
I just kegged a batch of stout a while back, and I had been using one of
those little bicycle pump-style C02 chargers to dispense it. It certainly
wasn't an amazing beer, but it was certainly drinkable. The problem I have
here is that it now smells and tastes awful. It has a burnt rubber-ish
smell to it, that hbd has always attributed to yeast autolysis. However, I
noticed that the CO2 cartridges I use kinda have that same smell, and I was
wondering if that might be another cause for it. The keg was left half
full, under pressure from the little CO2 cartridges for a few weeks, and it
is my guess that the smelliness of the cartridges caused the beer
smelliness. Has anyone else had a problem like this?
- --
Gregory Morris
Web Developer
Literati
(304) 296-8026 ext.139
gmorris at literati.com
------------------------------
Date: Wed, 24 Dec 2003 09:44:27
From: "C.D. Pritchard" <cdp at chattanooga.net>
Subject: re: How to throttle magnetic pump?
Brendan asked "...if the best way to throttle the flow is to (1) restrict
flow output or (2) use a dimmer switch to reduce power to motor. I
understand that reducing motor speed would also slow the cooling fan, but I
guess I could cool externally. Does outflow restriction have any negative
impact on pump/motor? "
Either is fine IMHO. For a RIMS or HERMS, it's been posted that pumps can
damage enzymes but my experience doesn't support it. I switched from a
discharge valve to a ceiling fan controller for the March MDX-3 RIMS pump a
couple of years ago and didn't notice any change. Don't worry too much
about motor heating- Although mine runs at much less than 1/2 speed for
around an hour while mashing, there's been no motor overheating.
Some tips if you go with a changing pump speed- at least for a March MDX-3:
1) A lamp dimmer won't work- use a ceiling fan speed controller. 2) Not
all fan controllers work. I tried a couple before I found one which
worked. The metal mounting plate is marked "Lutron FS-5F" - made by
Leviton as I recall. 3) a variac (variable transformer) didn't work.
Given the above, I'd been better off sticking with a valve to throttle the
flow. If you go with a valve, a globe or even a gate type works better for
throttling flow than a ball valve- often opening or closing a ball valve
just a few degrees greatly/disproportionally changes the flow.
c.d. pritchard cdp at chattanooga.net
http://chattanooga.net/~cdp/
------------------------------
Date: Tue, 16 Dec 2003 06:43:52 -0800
From: "Parker Dutro" <pacman at edwardwadsworth.com>
Subject: RE: Throttling Outflow of Magnetic Pump
The safest way to control output is to use a ball valve or other
adjustable valve on the exit port of the pump. For obvious reasons
restricting flow to the entry port would cause the pump to cavitate.
With magnetic pumps, it is alright to shut the output valve all the way
off. I do this occasionally and the motor just spins and spins until I
open the valve again. I don't do this for extended amounts of time; it
would be advisable to switch the pump off instead to save from
overheating and overworking it.
"To every man, in his acquaintance with a new art, there comes a moment
when that which before was meaningless first lifts, as it were, one
corner of the curtain that hides its mystery, and reveals, in a burst of
delight which later and fuller understanding can hardly ever equal, one
glimpse of the indefinite possibilities within." C. S. Lewis
------------------------------
Date: Tue, 16 Dec 2003 08:11:18 -0700
From: "Bob Speights" <rspeight at frii.com>
Subject: Beer on a German Tour
Stan,
Do try Heidelberg if time allows. Vetters Alt-Heidelberg Brauhaus is worth
a side trip. It's just off the church square in the center of town (Steing.
9). The fried sausages and potatoes are to die for (They make their own
sausages and, of course, beer.) Take a prodigious thirst. They have a half
dozen brews on tap at all times. And, do make ready to make friends - it's
that kind of place.
Enjoy,
Dr.Bob
------------------------------
Date: Tue, 16 Dec 2003 07:16:04 -0800
From: "Chad Stevens" <zuvaruvi at cox.net>
Subject: RIMS thermal density
In support of what Dion has already gotten across with what I thought was a
reasonable degree of clarity...(heat shields up):
For the love of Pete! The mash and the boil are two entirely different,
detached, and diametrically opposed events in the beer making process. In
the mash we want enzymes to remain intact; in the boil, we want to destroy
the little buggers. In a RIMS setup we're not worried about caramelization
or blowing up $7.00 heater elements or any other cataclysmic doomsday event
you might envision.
The central point is this: enzymes are not thermally stable. Get them too
hot in your heater chamber and they can't do that voodoo that they do so
well. Keep the watt density low!
I feel better now. Can we go back to talking about beer? Anyone made Malt
Vinegar? Pointers?
Chad Stevens
------------------------------
Date: Tue, 16 Dec 2003 09:30:28 -0600
From: "Ronald La Borde" <pivoron at cox.net>
Subject: 5 gallons per minute
>From: "Todd M. Snyder" <tmsnyder at buffalo.edu>
>
>But 5 gpm seems really really high to me. How can you get that much
flow
>thru the grainbed without compressing it? What flowrate do other
RIMSers
>use?
Well, having not been there, I cannot say for sure just how that is
done. However, I will tell you that I have never dreamed of achieving
5 gpm circulation rate. Oh, of course I tried to see just how much was
possible on my system. Never got close. My conclusion is that the
grain in the mash sort of semi-floats in the liquor, and when one
circulates rapidly, the grain is pulled down and gets compacted more,
more and more (3m). So, just how one gets 5 gpm flow rate is a mystery
to me.
I am not saying it cannot be done, but I don't know how. For a 5
gallon brew batch, I might get 1 gpm at the most. Normally when I do a
10 gallon batch, I will flow somewhere around .5 gpm. No matter how
good the filter screen, It seems to me that the limiting factor is the
grain's ability to float without compacting. Possibly with a super
wide and shallow grain bed it would be possible. My system uses an
Igloo 10 gallon cooler, and the bed will be about 15 inches deep. The
photos I see on some rigs do have a much shallower mash thickness,
perhaps this is the secret.
On the subject of temperature probe placement, If the flow stops, does
it really matter where the sensor probe is placed? This is why to my
way of thinking, a stuck mash is the kiss of death to the brewing
session using RIMS. The only way to keep the PID and heating element
at desired temperature with a stuck mash would be if you had the temp
sensor bonded to the heating element. That way the PID would be
getting a steady diet of truth.
For those who want to use computers, the ideal setup would be for
several sensor probes throughout the system. In the mash tun, one
probe at the top, one in the middle perhaps, and the computer then can
figure out the average mash temp, which is what we really want.
Ron
=====
Ronald J. La Borde -- Metairie, LA
New Orleans is the suburb of Metairie, LA
www.hbd.org/rlaborde
------------------------------
Date: Tue, 16 Dec 2003 09:35:10 -0800
From: "Mike Sharp" <rdcpro at hotmail.com>
Subject: Re: PID Control
Todd replies:
> Mike Sharp writes:
> "The maximum ramping rate has nothing whatsoever to do with the type of
> control--it's the amount of power you apply to the heating chamber. "
>
> I agree completely. But if you have a low flowrate of wort and you set
the
> heating chamber at the mash target temperature, it will take a long time
to
> heat the _mash_ up to the target temperature.
Well, if the flowrate is too low, the system is defective, and that's
another issue.
> My point is that if you could heat the recirculating wort _above_ the
target
> temperature to some safe but elevated temperature, you could get the heat
> into the mash faster and in something more closely resembling a step
instead
> of a ramp.
That's what PID will do, especially if you put the probe in the mash, the
wort is hotter exiting the heater. You need to control the "amount hotter"
by setting the max "on" cycle time. So when beginning the step, with your
probe in the mash, you must configure your output so that when the
controller is below the proportional band, the output is fixed to some
maximum value (depends on the system thermodynamics). But this is risky,
because you don't really know how hot the wort is getting at the exit of the
heating chamber.
It's possible to combine two controllers to do this so that you:
1. Control the max temp of the wort in the heating chamber
2. Directly control the mash temp.
You have two separate controllers, one set for PID control with a probe in
the mash, the other set for proportional control (PID is unnecessary here)
with the probe at the outlet of the heating chamber. Ideally, you use an
instrumented heating rod, as this has the fastest response time. This has
the TC embedded in the end of the heating element (some have it in the
middle, but these are used for other purposes). I have a heating chamber
(which I actually use for other purposes) that is a straight cartridge
heater with a K type TC embedded at the end of the rod. It's a fairly
standard cartridge heater, and the heating chamber is a straight stainless
tube with a swagelock T at both ends. The heater enters the "in" end, and
sticks about 3/4 of the way up the tube. I'll post a picture this weekend.
Anyway, the way this works is the two controllers control separate SSRs
wired in series together with the heating element. When the system begins
the step, the PID controller in the mash goes to 100%, because the mash temp
is well below setpoint. The P controller in the heating chamber is also at
it's max value, which depends on your system. Let's say you run your
element at 100% power, because you have a low enough watt density.
Very quickly the chamber heats up (but the mash hasn't). The P controller
enters it's proportional band, which is set so that the max temp of the PB
is the max "safe" temp for the wort. The heating chamber gets to the final
temp quickly as the the P controller begins cutting back on output. Even
though the mash PID controller is at 100%, the heating chamber controller is
the one controlling power to the heater. Increasing flow at this point
will cause the P controller to increase it's output, but temp will never go
above the max safe temp. Let's say your controller stabilizes at 60% power.
In practice, this actually decreases slowly as the incoming wort gets
hotter.
As the mash heats up (and it's doing it as fast as it can, given your
systems characteristics), it eventually enters it's own PB, and the SSR
(which has been wide open until now) begins to cut back. At some point,
it's going to have a lower output than the SSR for the heating chamber.
Remember, both SSRs are in series, controlling the same heater. The
controller with the lower percent output is the one that actually controls.
It's like having to valve in series. One can be wide open, but if the other
is mostly shut, it's the one that controls the flow.
Once the PID controller begins lowering output (as the mash heats up), the P
controller will slowly increase it's output to your max setting (assume 100%
for this example), because it sees heating chamber temperature falling, and
it tries to raise it. But it doesn't matter, because now power is
controlled by the mash temp.
This approach allows 1. Exact mash temp control and 2. the fastest
possible heating time.
power-----| Mash SSR|-----|Heat Chamber SSR]----Heater
>
> For example, lets say you want the mash to be raised to 154F and that you
> don't want the heating chamber outlet to exceed 160F. A PC based
controller
> could add the heat as fast as possible without exceeding the 160 limit.
> When the heater has been 'on' the total number of seconds needed to add
the
> required heat, the software stops adding heat even though the target
> temperature may not have shown up at any of the sensors.
This is called "feed forward" control. Some systems--especially systems
with long lag times from the time the controlled variable is changed to the
time the wild variable is perceived to respond--can only be controlled by
feed forward. The symptom is that with "feedback" control, the wild
variable oscillates around the setpoint, and cannot be tuned in, or else it
overshoots very badly, no matter what the tuning. Most modern process
controllers that do PID allow feed forward control, but this is much harder
to tune, and you must know the system thermodynamics intimately. It will
change with different mash schedules. With systems that do not have fixed
characteristics, it's difficult to come up with the tuniing parameter.
You can obviously do the control with a PC, but what you're doing is
essentially the same thing a dedicated process controller would do. You'd
be better off using the PC as an MMI front end to the process controllers,
and modify tuning parameters based on recipe selection which would be
derived emirically, unless you remember more of your college thermo than I
do...
>
> A PID is not smart enough to dump the heat in all at once. It 'sneaks up'
> on the solution with time when the temp sensor is installed on the outlet
of
> the heating chamber.
This isn't necessarily a characteristic of PID control, it's a
characteristic of "feedback" control, which may be PID or not. A simple
thermostatic control exhibits this same characteristic.
>
> Then Mike missed the point about the scenario involving the probe
somewhere
> in the mash, which _will_ cause a time delay in the control system.
>
Reasonable time delays can be tuned. Excessive time delays are symptoms of
poor design. If the rare case occurs where the time delay is inevitable
(especially if the delay is due to measurement delay, and not actual process
delay), then you must use feed forward control. An example would be if you
had a massive thermowell, and the mash heats up but it takes several minutes
for your probe to measure it.
Regards,
Mike Sharp
------------------------------
Date: Tue, 16 Dec 2003 14:59:36 -0500
From: Marc Sedam <marc_sedam at unc.edu>
Subject: natural chocolate flavoring
This topic comes up every now and again, from someone wanting to clone
either Rogue or Young's Double Chocolate Stout.
What you need to get is, really, called natural chocolate
flavoring/extract. The one place I'm certain carries it is Williams
Sonoma. At $10 for an 8oz bottle, it it a pricey little bugger. I
don't know if you need a full bottle per batch or not, but that's what
you need to get the chocolate flavor.
I've successfully used cocoa in brewing but then you have to balance the
bitterness of the cocoa with the bitterness of hops, etc. Can be hard
to get right.
Cheers!
Marc
- --
Marc Sedam
Chapel Hill, NC
------------------------------
Date: Tue, 16 Dec 2003 15:37:17 -0600
From: "Rob Dewhirst" <rob at hairydogbrewery.com>
Subject: creating clear canned wort
I have canned wort in a pressure canner in the past, for use with starters.
The base was light DME.
I stopped doing this because there was so much break material in the canned
wort. I tried pre-boiling and then canning, but it did not help much.
Any suggestions?
------------------------------
Date: Tue, 16 Dec 2003 14:39:25 -0800
From: "David" <gates at island.net>
Subject: Re: How to throttle magnetic pump?
>I've got a new magnetic pump (from morebeer.com) and was wondering if
the best way to throttle the flow is to (1) restrict >flow output or (2)
use a dimmer switch to reduce power to motor. I understand that reducing
motor speed would also slow
>the cooling fan, but I guess I could cool externally. Does outflow
restriction have any negative impact on pump/motor
>Thanks in advance.
Brendan,
Throttle the output of the pump. The pump is a non-positive
displacement pump so the normal practice is to throttle the output; this
will not have any sort of adverse effect on the pump. Having said that,
don't shut off the output and leave the pump running as you will burn
out the seal on the pump and render it useless.
David Gates
Victoria, BC
------------------------------
Date: Tue, 16 Dec 2003 18:35:40 -0500
From: David Towson <dtowson at comcast.net>
Subject: Re: RIMS Temperature Control
Wow, I've been away from the digest for a couple days, and there's been a
lot of interesting stuff posted on this subject. Particular thanks to
Steve for his good answer to my question about why rapid temperature steps
are desirable, at least across the 122 - 140 F range.
Todd asked some specific questions about my system performance, and I'll
try to answer them now. I have a 3-tier system using 15-gallon stainless
steel vessels. Each vessel has a natural gas burner under it, and I have
individually ported the burners to get different heating rates. The HLT
burner puts out the most, the kettle burner is next, and the mash tun
burner is quite a bit lower than the other two. I only use the mash burner
to pre-boil my water, and to provide a little boost heat during ramps, and
then it's throttled way back so as not to overheat the wort under the false
bottom.
I had never measured the flow rate during recirculation, so I had to
conduct an experiment to estimate that. I set everything up as usual,
except that I used only water in the mash tun, and I put a bucket inside to
collect the water so I could measure it. I have learned from experience
how much I can open the throttling valve on the pump discharge before I
risk sticking the mash, and that's where I set it for this experiment. I
ran four trials, and averaged about 1.6 gallons per minute. For
comparison, I ran one more trial with the throttling valve wide open and
got 2 gallons per minute. In all cases, the water was being pumped through
the HERMS coil, which offers a very substantial impediment to flow (45 feet
of helf-inch copper tubing, plus five feet of half-inch hose and assorted
plumbing hardware. In an actual mashing situation, I expect the rates will
be a bit lower due to increased pump suction caused by the grist.
Todd also asked about ramp rates. I only make one beer regularly that
needs stepping, and that's an oatmeal milk stout. I do a glucan rest at
108, a beta rest at 138, an alpha rest at 157, and mashout at 170. I have
clocked the ramp times on occasion, but never wrote them down. However,
based on my memory of the most recent times, the ramp rate runs between
about 1.0 and 1.5 degrees-per-minute depending on the temperature
difference between the step temperature and the HLT temperature, with the
greater difference giving the faster ramp as expected.
While reading the various posts, it occurred to me that perhaps a different
approach might be useful in addressing the question of whether a "fancy
controller" can provide much faster steps in an electric RIMS. Let's
assume for sake of discussion that all heat transfer is perfect, and there
are no losses whatever.
This example is for a step from 100 F to 150 F, a difference of 50 degrees,
which roughly equates to a step from a glucan rest to a low single
saccharification rest. From some web sources, I determined that water at
125 degrees (the midpoint temperature for this example) has a density of
about 8.25 pounds-per-gallon. And since one Btu will raise one pound of
water one degree F, it will take 8.25 x 50 = 412.5 Btus to raise one gallon
50 degrees.
I do 10-gallon batches, which seems pretty common for RIM/HERM systems, and
my usual amount of mash water is eight gallons. That's how much it takes
to cover my temperature probe, which is installed in place of a dial
thermometer that came with my equipment (a Sabco keg). So there's no fancy
reason why I put it there; it's just where I could put it. I did, however,
intentionally keep the probe short, so it "sees" the temperature near the
outside of the keg, where the heat loss is greatest.
Going on with the example, to raise 8 gallons 50 degrees, will take 412.5 x
8 = 3300 Btus. Now, here's where we get to the meat of this example. To
develop one Btu in one hour takes 0.293 watts. So using the example target
of 3300 Btus and this relationship, we can generate the following table
showing the power needed to get our 50-degree temperature change in various
fractions of an hour.
5 minutes 11,603 watts
10 minutes 5,801 watts
15 minutes 3,868 watts
20 minutes 2,901 watts
30 minutes 1,934 watts
These are the powers needed to raise 8 gallons of water through the example
50-degree step in the times indicated. And this is for a perfect system
with no losses, with the heater turned on full, and left on until the job
is done. In other words, there is no controller - just a switch, and
heating occurs at the maximum possible rate.
But a real electric RIMS is not a perfect system, and it has losses. So
more watts than those shown above will actually be needed to do the
50-degree step in the times shown. The reader can scale the above powers
upward by whatever factor seems appropriate to account for system losses,
but whatever the factor, were talking some serious power levels here for
rapid steps. And unless those watts can be converted into heat in the wort
in the specified time without damaging the wort through excessive local
heating, the indicated step times cannot be achieved no matter what kind of
controller is used.
I have no experience with an electric RIMS, but I suspect that doing really
fast steps with such a system will require a truly huge multi-element
heating chamber and a high flow rate, in order to have the power needed
while keeping the wort temperature within a safe range. If I were building
such a system, I'd want to have solved that problem before I spent a lot of
time thinking about a fancy controller.
Dave in Bel Air, MD
------------------------------
Date: 16 Dec 2003 18:41:56 -0800
From: Dion Hollenbeck <hollen at woodsprite.com>
Subject: Re: RIMS Ramp Rates, PID Controlled etc
>> FRASERJ writes:
JMF> I am guessing a PID Controller would throttle my system using
JMF> power control (cutting back on wattage) better than my hard
JMF> ON/OFF control of the elements would.
Actually, the PID controller does the same thing, ON/OFF only. It
does not directly cut back on wattage. There are some PID
controllers capable of outputting a voltage level corresponding to a
percentage of full on, but I don't see how that could control a heater
element without some more sophisticated electronics sitting between
the element and the PID capable of sensing the PID voltage level and
translating it into some sort of sine wave clipping like a dimmer
switch does. Most likely possible to do, but most RIMS systems I know
of use PID controllers that do ON/OFF, varying the percentage of
ON/OFF as the setpoint is neared or lost. This percentage and the
number of seconds one ON or OFF unit is can generally be set in the
PID.
dion
- --
Dion Hollenbeck Email: hollen at woodsprite.com
Home Page: http://www.woodsprite.com
Brewing Page: http://hbd.org/hollen
------------------------------
End of HOMEBREW Digest #4428, 12/17/03
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