How big can I brew in bayou 1044 11 gallon pot?

[Jayjay1976]

My largest successful grain bill so far was 12.5 lbs for a 5.5 gal. batch of saison; since my fermenter holds 7.5 gallons I'd like to try filling it with a larger batch and I'm wondering what are the limits?

 

[mirthfuldragon]

If you use Fermcap-S in the boil you can probably hit 9.5 or maybe 10 gallon volume without major risks in an 11-gallon pot. It will also carry through to the fermentation so that the krausen is thick, dense, and very low (1" or so), so a 6.5 gallon net to the fermenter is possible. Check your oxygenation processes though, since with that little head space there won't be a lot of O2 for the yeast to consume to reproduce early on in fermentation.

Fermcap-S is great. I do 3 gallon net to fermenter batches in a 4g pot on my stove, and my boils start at 3.75 gallons. I drain into a 5g bucket and then top-up the boil kettle during the boil, so my total boil volume over the course is nearly 5 gallons in a 4 gallon pot.

 

[Jayjay1976]

Thanks for the input! I already use fermcap, works wonders and that's what has me thinking about putting all that unnecessary fermenter headspace to work. I'm bottling so I can adapt to any batch size, would be nice to increase my yield on brewday.

 

[wilserbrewer]

Well "theoretically" with a huge grain bill say 20 lbs, and a batch sparge in a large bucket or another kettle, then closely boiling to the rim and topping up the kettle with more runnings a tad as you boil off, then slightly topping off the fermenter with water you could make a 10 gallon mid gravity batch....

Challenging and at the top end but doable....

 

[nDub]

I have that kettle and I've done an 18# grain bill.

My efficiency went way south for some reason.

Anything over 15# is more or less a wash for me, so I'll add extract to the boil if I need more fermentables after mash.

 

[rlonardo]

I've done 19# in a Bayou 10 gallon pot. BIG Russian Imperial Stout - OG was around 1.120. It was........close.

 

[Jayjay1976]

Is there a special mash profile or perhaps a longer mash time I could try to help boost efficiency in larger beers?

 

[nDub]

Is there a special mash profile or perhaps a longer mash time I could try to help boost efficiency in larger beers?

I typically do a thinner mash (more water per lb grain) for better efficiency so... you need more space for more water!

I'm not sure why it works like that for me. Might have something to do with my set up. I use a really fine mesh bag and the steamer insert and I think it causes some "dead space". Where there is water/wort outside the bag and not in contact with the grain.

I've had the water level drop due to absorption or flowing out of the bag slowly and the grain bed settle significantly.

Anyway long story short I just use a lot of strike water. And the more grain I use the less water I can fit.

This, of course, is all anecdotal and speculation.

 

[BeardedBrews]

Is there a special mash profile or perhaps a longer mash time I could try to help boost efficiency in larger beers?

@doug293cz is the BIAB mash thickness / conversion / efficiency math expert, but there are things you can do to help.

http://braukaiser.com/wiki/index.php/Understanding_Efficiency#Conversion_efficiency

You can fit 28 pounds of grain into an 11 gallon pot at a mash thickness of 1.25 qt/lb. You'll need to extend out your mash duration considerably, and recirculating or stirring will help. That would leave you with ~7.4 gallons after grain absorption, and as much as 1.096 pre-boil gravity if everything converted.

If you boil that down to 5 gallons you're at 1.142
If you dilute that up to 10 gallons you're at 1.071

If you dunk sparge with an extra 5.5 gallons you'll probably get second runnings at 1.040. You could use those to top off the and possibly push the 10 gallon batch up to 1.078, or you could use that second running to make a second beer.

 

[Jayjay1976]

Thanks for the input! The possibility of brewing s strong beer then getting another lighter gravity out of the same batch is really interesting, I'd like to try that.

 

[BeardedBrews]

Thanks for the input! The possibility of brewing s strong beer then getting another lighter gravity out of the same batch is really interesting, I'd like to try that.

You could add grain too in the second run, for color, or flavor, or whatever.

 

[doug293cz]

Is there a special mash profile or perhaps a longer mash time I could try to help boost efficiency in larger beers?

There are two things that reduce efficiency with larger grain bills. The most important is the extra amount of wort that is absorbed by the extra grain. All the wort absorbed by the grain contains sugar that you would rather have in your BK, so the more that gets held by the grain the lower your efficiency. You can mitigate this effect with sparging and/or squeezing (if BIAB), as both reduce the amount of sugar retained by the grain. The second effect, that may or may not occur, is lower conversion efficiency. Thicker mashes convert at a slower rate, so may take more time to convert fully. Longer mash times, stirring and/or recirculation will mitigate this.

Here is a chart that shows how lauter efficiency drops off with larger grain bills. The "X" axis is 'grain weight/pre-boil volume,' which makes the chart independent of batch size. You can see the effects that various numbers of sparge steps has, as well as the effect of reducing grain absorption (squeezing.)

Mash efficiency equals conversion efficiency times lauter efficiency, so if both of those go down with larger grain bills you get a double whammy.

If you want to play with different scenarios, you can grab a copy of my mash/sparge simulator here. It calculates the mash volume from all of the other inputs. Conversion efficiency is a input parameter, so you can try various assumptions for that if you want.

Brew on

 

[nDub]

There are two things that reduce efficiency with larger grain bills. The most important is the extra amount of wort that is absorbed by the extra grain. All the wort absorbed by the grain contains sugar that you would rather have in your BK, so the more that gets held by the grain the lower your efficiency. You can mitigate this effect with sparging and/or squeezing (if BIAB), as both reduce the amount of sugar retained by the grain. The second effect, that may or may not occur, is lower conversion efficiency. Thicker mashes convert at a slower rate, so may take more time to convert fully. Longer mash times, stirring and/or recirculation will mitigate this.

Here is a chart that shows how lauter efficiency drops off with larger grain bills. The "X" axis is 'grain weight/pre-boil volume,' which makes the chart independent of batch size. You can see the effects that various numbers of sparge steps has, as well as the effect of reducing grain absorption (squeezing.)

View attachment 548136
Mash efficiency equals conversion efficiency times lauter efficiency, so if both of those go down with larger grain bills you get a double whammy.

If you want to play with different scenarios, you can grab a copy of my mash/sparge simulator here. It calculates the mash volume from all of the other inputs. Conversion efficiency is a input parameter, so you can try various assumptions for that if you want.

Brew on

Sweet! That validates my experience with science. I’m excited to try your simulator.

Thanks!