Half (or at least less than 5 gal) batches?

OK, so let me start by saying I have not yet invested in brewing software. So this question comes with a handicap up front.

But ... I have been shying away from making some of my favorites (barley wines and Imperial Stouts) because my 10 gallon cooler simply will not handle the volume of grain needed. I have been pushing the limit of my cooler with 16 or 17 pounds of grain. A beer like the ones I am envisioning will easily cross the 20 pound mark for 5 gallons.

So my homebrew addled mind finally hit on what should have been the simplest of ideas. How about cutting the size of the batch to either 2.5 or 3 gallons? DUH!

So now it gets me to thinking about how to properly scale down a batch. I use an online calculator that predicts gravities and IBUs based on batch size, boil volume and amount of grain used. So I can scale down the base ingredients with no problem to ensure I hit the same gravities and bitterness. And quarts per pound is quarts per pound no matter how much grist I have. So my mash water volume is no problem.

The main thing that's puzzling me is pre boil volume. I usually batch sparge to collect 7 gal of pre-boil wort to get to a final volume of 5 to 5.5 gal. But how do I calculate what to collect for a 3 gal or even a 2.5 gal batch? My boil rate is not consistent because I am usually cleaning during the boil. Sometimes I wind up at 5 gal. Sometimes 5.5, Sometimes somewhere in between.

So I have 3 questions:

1. Am I right in thinking that I can use a calculator to scale a batch down from 5 gallons and if everything else remains the same, I can still create the same beer, just less of it?

2. What's the best way to predict what changes I would need for the smaller volume? I am particularly concerned about how much to collect pre-boil.

3. Is there anything else I should be considering when looking to scale down a recipe?

1. Yes

2. Figure out your boiloff rate. I go for 15%. So when I make a 6gallon batch, I start with 7.06 gallons preboil.

7.06 - (15%*7.06) = 6gal

or put another way:

6gal/85% = 7.06 gal

3. I still think it's better to spend the money on the extra DME and make a full sized batch... when you have a really delicious, high alcohol, complex beer, you'll be kicking yourself when you only have 24 bottles of it. Especially when you drink that last bottle...

kanzimonson said:

3. I still think it's better to spend the money on the extra DME and make a full sized batch... when you have a really delicious, high alcohol, complex beer, you'll be kicking yourself when you only have 24 bottles of it. Especially when you drink that last bottle...

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I have 3, 5gal glass carboys that have been sitting in my attic collecting dust. 3 gallon batches that need to sit in something for a long time, that I am afraid to age in plastic? Sounds like a match made in heaven.

And with 3 glass fermenting/aging vessels, I can afford to make a case at a time and keep them coming. The kinds of beers I want to make in these are beers that I plan to set aside for some aging anyway.

Am I wrong?

kanzimonson said:

2. Figure out your boiloff rate. I go for 15%. So when I make a 6gallon batch, I start with 7.06 gallons preboil.

Click to expand...

So I was a bit optimistic in my first post. I generally start with 7 gallons on the nose. I brewed twice over the past weekend. Beer #1 hit the 5 gallon mark dead on when it went into the fermenter. So that puts my evaporation rate at around 29% for an 80 min boil on that beer. The numbers look right but that seems like a lot of loss to boil. Came awfully close to my estimated gravity though.

The darndest thing is that it never seemed to hit an overly vigorous boil. More like a steady, rolling simmer.

Beer #2, I spent a little more time fluctuating the heat so that I never really spent too much time at any sort of boil that you would call "rolling". I've only marked my BetterBottle at 1 gallon increments so I "eyeballed" that one to be about 5.25 gallons on a starting volume of 7 gallons. That puts me at around 25%.

Nope. My first 4 extract brews were 5 gallon batches. My last 4 brews (now AG) are a 1gal Smoked Porter, a 3 gallon Oktoberfest, and a 4 gallon Pumpkin Spice Ale.

I'd rather brew small batches, with more variety, and brewing more often, then have 5 gallons of something. So what if I run out of a 1/2 batch (2.5 gallons) of something good? Since I only did a half batch, brew it up again! It's fun to brew

By the way, I use Beersmith to scale my recipes down. But you can probably get pretty close by halving everything for a 5 gallon batch to get down to a 2.5 gallon recipe. Going from 5 gallons to 1 gallon gets a little trickier because you'd have to watch hop utilization, but it works in general just to chop it down in whatever proportion you're making.

I might be wrong (not much all-grain experience), but I don't see why you couldn't do a thicker mash and be fine with what you have, as long as you parti-gyle (or no-sparge). A 10-gallon cooler should be able to fit 24 lbs of grain @ 1.25 qts water/lb grain, and easily give you an OG of 1.120-1.130 (~75% efficiency) for 5 gallons.

Bobby_M said:

...a 10 gallon mash tun can do 5 gallons of 1.118 barleywine (~11% ABV) and 10 gallon batches of 1.060 IPA (~6% ABV).

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winvarin said:

So I was a bit optimistic in my first post. I generally start with 7 gallons on the nose. I brewed twice over the past weekend. Beer #1 hit the 5 gallon mark dead on when it went into the fermenter. So that puts my evaporation rate at around 29% for an 80 min boil on that beer. The numbers look right but that seems like a lot of loss to boil. Came awfully close to my estimated gravity though.

The darndest thing is that it never seemed to hit an overly vigorous boil. More like a steady, rolling simmer.

Beer #2, I spent a little more time fluctuating the heat so that I never really spent too much time at any sort of boil that you would call "rolling". I've only marked my BetterBottle at 1 gallon increments so I "eyeballed" that one to be about 5.25 gallons on a starting volume of 7 gallons. That puts me at around 25%.

Click to expand...

Let me explain that I'm actually talking about hourly boiloff rate. You should be aiming to boil off 15% of your wort per hour. Here is the expanded formula for figuring it out: