Batch Size

[sremed60]

I'm in the process of going from extract to all-grain. I had the great idea of doing 1 gallon test batches. I could brew a lot more often, tweak recipes, do a lot more experimentation, and in the end I'd have a lot more variety in the beer I'm drinking. Then when I hit on a recipe I was happy with I could scale it up to a 5 or 10 gallon batch.

The problem I've run into: water boils off at the same rate in a 60 minute boil regardless of the batch size. So if it's boiling off at 1 gal per hr, that's a 50% loss for a 1 gallon batch vs a 20% loss on a 5 gallon batch or 10% on 10 gallons.

Is there a formula that accurately compensates for thar? Or is brewing ten 1 gallon batches the only sure way to get 10 gallons of the same beer from a 1 gallon recipe?

 

[Reisende]

That's a really neat idea, I like it!

I think you already answered your question though: you lose the same fixed amount of wort in a 60 min boil. So, mathematically, your boil-off calculation looks like this:

Post-boil vol = Pre-boil vol - X

OR

Needed Pre-boil vol = Desired Post-boil vol + X

"X" being your 60 min boil loss. You only need to increase your pre-boil volume by "X" to end up with the right amount of wort

Now, I see exactly why this is messing with your grand scheme. If you add, lets say 1 gal of wort to a 5 gal batch to compensate, that's not such a huge deal with boil gravity and hop utilization. Do the same thing to a 1 gal batch, and you just drastically changed the outcome of the beer. I see two easy options for you here:

#1 - use some brewing software to calculate volumes and gravities for your 1 gal recipes.

#2 - Get a smaller kettle for the 1 gal batches, which will reduce your boil-off.

You could always manually adjust your recipes, but that math is hard (or at least long). I use BeerSmith, but there are many free options, and probably some spreadsheets on this forum that can help you. Software would really help when you start scaling things, especially for hop utilization.

Sorry if this was long, Prost!

 

[bendog15]

Get beersmith. It does all calculations for you.

 

[sremed60]

That's a really neat idea, I like it!

It seemed like a good idea at the time, BUT... Even as I was typing the question I realized the ridiculousness of it. Consistency from one batch to another would obviously have to be a huge concern for commercial brewers, and they just have to worry about making sure one 200 gallon batch is the same as the next 200 gallon batch. Being off a gram or two on a hop addition probably isn't a major concern. I would "guess" that smaller your batch size gets, even down to the 5 or 10 gallon range, the more difficult it becomes to be consistent between batches. And I would further "guess" that trying to achieve consistency between a 1 gallon batch and a 5 gallon batch probably would require a lot more time, effort and knowledge than its worth.

I read one thread where someone said, "I could give ten guys the same recipe and ingredients and get back ten different beers."
If that's true, (and it sounds like it is), then there's obviously too many variables to take into account at the 1, 2, 3, 5 or even 10 gallon level.

 

[Reisende]

You are spot on. I still think there is merit to 1 gal batches, but you would have to be pretty precise. I don't know that I would completely abandon the idea, you could still use it for testing styles or major recipe changes, then dial in a specific recipe on a 5/10 gal batch.

What ever you choose, good luck.

 

[sremed60]

Yeah, The idea of being able to brew five times more often is appealing, and having a gallon of 5 different beers stored vs. 5 gallons of just one beer is also appealing too. Even when I buy commercial beer, I buy the variety 12 packs with 4 different styles or the mix and match 6 packs.

Theres just way too many beers out there to try and even more to brew - I can't see getting bogged down drinking the same one over and over again. He he he.

 

[C-Rider]

I do 2 gallon batches in a 3 gal cooler BIAB (5g in the video) fermenting in 2 gal buckets from HD. I get 3 six packs per brew and as you can see I have lots to choose from.

 

[Jim311]

I must drink too much because it's rarely a problem to drink 5 gallons of beer, or find enough friends to help me consume it pretty quick.

 

[Oginme]

Your thinking on the boil off is correct IF you maintain the same thermal input for a 1-gal batch as with a 5-gal batch. Generally, because there is less water to heat to boiling and needed to maintain boiling, you will turn the heat down to get the same quality of boil.

I get a higher boil off rate with my 10 liter batches as with a 20 liter batch, but it is not a set rate. My boil off rate is 2.1 lph on a 10 liter batch and 2.62 lph on a 20 liter batch.

BTW, I use my 10 liter batches (which gets me about a case plus a couple of 12-oz bottles) for my recipe development. A case of beer doesn't last too long (except that I brew many more times and many more recipes during a given year). The plus side is that I can use 3-gal carboys or buckets for fermenting and, when I have all six filled, I can turn it down to 9 liter batches and use my Mr. Beer Kegs (which are remarkably cheap in comparison).

Once I have my recipes set, I step up to a 20 liter batch to stock up on a given recipe for a while.

Another plus I have found is that I don't go through IPAs or pale ales as quickly as I do other styles. 10 liter batches ensures that I brew them more often and they are fresher, without a loss of hop aroma.