Author Topic: Does shape of Tun matter?  (Read 1879 times)

Offline duboman

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Re: Does shape of Tun matter?
« Reply #15 on: November 08, 2011, 02:38:19 PM »
recipe and procedure:

8.8lbs 2 row
1.6lbs Caramel 40L
14oz Munich
14oz Victory
9oz chocolate

Hops
1.25oz Northern Brewer-60min
1oz cascade-60 min
1oz cascade-0 min
1oz Saaz-0 mmin

Wyeast 1056
1 oz cascade dry hop 7 days
.5 oz saaz dry hop 7 days

Single infusion med. body batch sparge
Mash in 3.82 gallons at 168/step 156
Drain-sparge 2.07 gal, drain sparge 2.07 gal (15 minutes between)
Grain absorption at 1.42 and .25 dead space
6.25 gallons wort with 1.25 gallon boil off at 60 minutes
(Because we added hot water to raise temp during mash we actually got 6.75 gallons wort, experienced our first boil over but not terrible and still got our 5 gallons of wort)

Total grain bill was 12.2lbs which is why we needed to change tuns as the 5gal was not large enough with the required water to mash, last time we tried something this big the water oozed out when we put on the lid.

We used the same screen and valve for the cooler, no false bottom. Mash was stirred every 15 minutes and temp was checked at the same time, hence the adjustment. Hope all this info helps, I am still thinking the temp variables are to blame. ::)
Peace....Love......Beer......

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Offline malzig

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Re: Does shape of Tun matter?
« Reply #16 on: November 08, 2011, 03:53:32 PM »
Duboman, how much grain would be typical of a 75% batch?

Not that it couldn't be the temp. You might want to cut down on the stirring to reduce heat loss, by the way.
« Last Edit: November 09, 2011, 10:07:36 AM by malzig »

Offline DaveR

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Re: Does shape of Tun matter?
« Reply #17 on: November 09, 2011, 08:43:59 AM »
On a slightly different note, how important is water chemistry to efficiency? Can it be a factor? I ask because last spring I started using all RO water and adding minerals back. I forgot to add the minerals to one batch last summer. My efficiency in that batch went from my normal of over 75% to the mid 60's. Could be I'm overlooking something else, but the only significant variable I can think of is the water chemistry. Can the water profile affect efficiency?

Offline davidgzach

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Re: Does shape of Tun matter?
« Reply #18 on: November 09, 2011, 09:00:03 AM »
Absolutely.  It wil effect your ph which in turn directly effects conversion.  Have you checked mash ph at all?
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Offline bluesman

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Re: Does shape of Tun matter?
« Reply #19 on: November 09, 2011, 10:53:34 AM »
What was your mash pH?
Have you calibrated your hydrometer?

Some things to consider are the crush, mash pH, temperature, mash thickness (try thinning the mash a bit 1.5:1 or better) and increasing mash time. If the crush is on the coarse side then increase mash time until complete conversion has been achieved. Use a Refractometer to check the mash if you have one. Mash pH is also important (5.2-5.7). I use a pH meter but pH strips are okay. Mash thickness can be thined by adding more water to a thickness of 1.5:1 or better which will also help the conversion process. Also get your thermometer calibrated or buy a lab grade (NIST Traceable) thermometer to calibrate your working thermometers.

Mash conversion is a matter of time, temperature and proper mash pH.
« Last Edit: November 09, 2011, 10:56:06 AM by bluesman »
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Offline duboman

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Re: Does shape of Tun matter?
« Reply #20 on: November 09, 2011, 02:54:44 PM »
I appreciate all these great replies and things to look for, since I have not been an AG brewer all that long I believe it is time to put a little more science into process, but all in all the beer's been great-thanks!
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Offline DaveR

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Re: Does shape of Tun matter?
« Reply #21 on: November 10, 2011, 11:33:22 AM »
What was your mash pH?
Have you calibrated your hydrometer?

Some things to consider are the crush, mash pH, temperature, mash thickness (try thinning the mash a bit 1.5:1 or better) and increasing mash time. If the crush is on the coarse side then increase mash time until complete conversion has been achieved. Use a Refractometer to check the mash if you have one. Mash pH is also important (5.2-5.7). I use a pH meter but pH strips are okay. Mash thickness can be thined by adding more water to a thickness of 1.5:1 or better which will also help the conversion process. Also get your thermometer calibrated or buy a lab grade (NIST Traceable) thermometer to calibrate your working thermometers.

Mash conversion is a matter of time, temperature and proper mash pH.

Many thanks for all the feedback!

I usually brew pale beers that are moderately to highly hopped (although I'm now trying different styles).

I crush every batch the same. I run the grain through a Barley Crusher, twice. It left it at the factory setting.

I normally mash at 1.25 quarts per lbs. I shoot for 152 (154 high, 150 low). Mash temp within the tun can vary, as you know. I mash for an hour and usually don't get much temperature drop. Two degrees at most. If I start on the low side (150) I may heat up a quart or two of mash at 30 min and add it back. Sort of a decoction, I suppose.

I have two hydrometers. I've calibrated both. One reads .002 low. I rarely use that one. If I do I factor in the adjustment.  I have some very accurate thermometers. Before digital photograhy I did darkroom work for years. Some of the tools segway nicely to brewing.  ;)

I use strips to test pH. It's usually around 5.2. Strips are sometimes hard to judge, but I'm sure the mash pH is always below 5.5.  A pH meter and refractometer are both on the list. I haven't bought either one yet. 

Unfortunately the time I forgot to put in the minerals -- i.e. used untreated RO water -- I also forgot to check the pH of the mash. It was an off day  :(  I figured pH might have been a factor in lower efficiency. 




Offline Will's Swill

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Re: Does shape of Tun matter?
« Reply #22 on: November 12, 2011, 08:51:23 AM »

This is because the amount of wort lost to the grain bed is directly proportional to the amount of grain. 


this implies the percentage and hence efficiency should be the same.  to lower the efficiency it would be wort lost is proportional to the amount of grain raised to some power. which may be the case. (in other words amount of lost wort increases faster than the amount of grain increases.)
I see where you're coming from, but you're making it more complicated than it is.  Essentially, for a 10# batch you lose 1.2 gallons to the grain bed, or 16% to hit 6.5 gallon pre-boil.  For a 20# batch, you lose 2.4 gallons, or 27%, to the grainbed. So, the amount lost increases faster than the total volume increases, but the amount lost is proportional the the grist weight.

So you're assuming the same pre-boil volume in both cases.  That makes sense. 

FWIW, I did an experiment that I posted about here some time ago where I brewed two batches of the same beer, but I doubled the second batch's grist in the same mash tun.  I was surprised to find that the larger grist retained significantly more water per pound of grain.  I'll have to repeat that sometime because I don't really believe the results and I think I probably made a measurement error somewhere.
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