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Brewing Topics => All Grain/Advanced => Topic started by: itsratso on August 28, 2014, 03:50:15 PM

Title: what is going on with one gallon recipes?
Post by: itsratso on August 28, 2014, 03:50:15 PM
in the middle of a brew day. I have been starting to do one gallon brews as an experiment to trial different things. so far things have been not going so well, but today was just off the charts ridiculous. I am brewing a one gallon smash with 2.6 lbs of Vienna. my pre-boil volume was 3.4 gal which I hit. OG on this beer is supposed to be 1.060, and my pre-boil gravity was supposed to be 1.039. I hit a preboil gravity of 1.020. that is not even close to the ballpark let alone near it. my efficiency for this brew was 35%. that's not even possible, the usual for me is 69%. why does beersmith show the estimated mash eff for this at 156%???
Title: Re: what is going on with one gallon recipes?
Post by: Oginme on August 28, 2014, 05:34:16 PM
Something is not right with your scenario.  You have 2.6 lbs of Vienna at 38 ppg which is 98.8 total gravity points.  At 100% efficiency your reading with 3.4 gal of wort collected would by a gravity of 1.029.  This puts your efficiency at right around 69%

I think your real issue is your volumes.  If you are making a 1 gallon batch size, why would you be collecting 3.4 gallons of wort?
Title: Re: what is going on with one gallon recipes?
Post by: itsratso on August 28, 2014, 06:21:05 PM
I know its a lot, but it is correct. I have a 1.25 trub/chiller loss, a .3 gallon fermenter loss, and boil off 1.1 gallon an hour. all of this is in my equipment profile, so it should all be accounted for by BS correct?

Title: Re: what is going on with one gallon recipes?
Post by: itsratso on August 29, 2014, 12:02:17 PM
i still cannot figure out how beersmith is figuring that 2.5 lbs of vienna in a 3 1/2 gallon preboil volume will give you a 1.060 beer. i have a thread running where we are discussing it and no one else seems to know either:

http://www.homebrewtalk.com/f39/1-gallon-brewers-unite-311884/index463.html

post #4623

edit: as discussed in the thread, i guess you could boil down to whatever OG you want. so the better question is how does BS figure i should get a preboil gravity of 1.039 when the preboil gravity i got (1.020) would give me a 70% efficiency which is almost exactly what my system efficiency actually is.
Title: Re: what is going on with one gallon recipes?
Post by: brewfun on August 29, 2014, 12:27:46 PM
Can you post the recipe as an export file? A simple report format won't help uncover anomalies.
Title: Re: what is going on with one gallon recipes?
Post by: itsratso on August 29, 2014, 12:38:31 PM
i will gladly do so but i am working a doubleshift today so it won't be until midnite tonight.
Title: Re: what is going on with one gallon recipes?
Post by: brewfun on August 29, 2014, 01:12:16 PM
So, just going through the numbers you posted, it looks like your system performed exactly as you expected.

You state an actual preboil volume of 3.4 gallons and SG of 1.020. That becomes a total of 68 gravity points, which divided by grist weight means you extracted 1.026/lb. This equates to 68% to 70% mash efficiency which allows some margin of error, but matches what you stated.

However, if you stated a BREWHOUSE efficiency of 69%, then that is simply not possible because your losses are just about equal to your yield. So, even if you have a mash efficiency of 100%, you still can't have a brewhouse yield of more than 51%.

The 35% efficiency number BS gave you is the calculated efficiency on the Fermentation tab, correct? Let's remember that this is the percentage or total available sugars that made it from the grain into the fermenter. Since you're already losing half the sugar to trub, the remainder is your mash efficiency difference.

A simplified version of figuring your brewhouse efficiency is the following formula:

BHE = (Sg x BV) / (Pg x GW)

BHE: Brew House Efficiency
Sg: Wort Specific Gravity, post chill (or post boil)
BV: Batch Volume, as measured in the fermenter
Pg: Potential gravity of grain
GW: Grain Weight

Based on the information you provided I estimated the post boil gravity. That means you got:

35% = (26.6 x 1.3) / (38 x 2.6)

I've cross posted this to the other forum, too.
Title: Re: what is going on with one gallon recipes?
Post by: itsratso on August 30, 2014, 12:19:33 AM
here is the file. I think based on your help on the other thread I have a rudimentary grasp on what is wrong, but I am unsure how to fix it in BS.
Title: Re: what is going on with one gallon recipes?
Post by: itsratso on August 30, 2014, 06:46:17 AM
mystery solved and a shout out to brewfun, who i may have a man crush on at this point. post #4648:

http://www.homebrewtalk.com/f39/1-gallon-brewers-unite-311884/index465.html
Title: Re: what is going on with one gallon recipes?
Post by: KernelCrush on August 30, 2014, 07:08:06 AM
He IS the man. We should all count ourselves as pretty lucky he finds the time to help here.