Nano-brewing

Has anyone had much experience brewing very small batches of beer? I'm talking 5l, which is about 1 gallon. The last two beers I've brewed have been this size batch, and I've run into a few problems, mainly with boil-off volume and losing wort to trub. I just pitched the yeast for a session 5% pale ale, and it looks I've ended up with 3l of beer rather than 5! I brew no-sparge BIAB, if that makes a difference. Should I try sparging? Any thoughts on this in general?

I brew 2gal batches and what I've done to dial in my process a bit is test my boil-off rate. This rate changes, but not drastically. On a typical 2 gallon batch I boil off a little more than a gallon. I'd recommend that you test your rate. Fill your brew pot with water. Use the amount of water that corresponds to your usual pre-boil wort volume. Bring it to a rolling boil (not leaping out of the pot) and set the timer for an hour. Measure before the boil and after the boil. That's your boil off rate. Now you can work backwards.

Say you want to END with 1 gallon in the fermentor. Let's say your boil off rate is 1.25 gallons per hour. That means you must start with 2.25 gallons pre-boil. Let's also factor how much is lost to trub. Say that's about .5 gallons. That means you'll now need about 2.75 gallons pre-boil. Any other losses (i.e. dead space), factor that in and you should be able to hit your numbers fairly close.

One thing to remember is that hot/boiling water expands. If you want the most accurate measurement of your boil off rate, cool your water down to pitching temps using the method you normally use. Then take your measurement. You could also take your volume measurement using hot water both time. Take your volume measurement just at the start of 60 minutes and just after flame out at the end of 60 minutes.

And if you boil off too much, you can always just add some water near the end.

MalFet said:

And if you boil off too much, you can always just add some water near the end.

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True. Just make sure it's clean. Don't want any nasties getting into your beer.

hafmpty said:

True. Just make sure it's clean. Don't want any nasties getting into your beer.

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Right. By "near the end", I mean near the end of the boil. I should have made that clearer.

Agreed...I do only 1 gallon batches and you really need to dial in your numbers and this won't be an issue. I start my boil with 1.87 gallons and end up with 1.15 exactly (at least for my IPA). After filtering and cooling, I get slightly over 1 gallon in my fermenters.

If you are using a 1 gallon carboy there is no way you are ever going to get 1 gallon for bottling, trub loss, blow off, and racking will leave you with less. At best I get 7 16 oz bottles, at worst, 5 with a half-pint sample.

Two things you can do...break your batch into 2 1-gallon jugs and brew 1.25 or so gallons, you'll get 1 gallon in the end. Or get a larger fermenter for it and do the same. I simply due back to back brews so I only have to use one yeast packet and I get a 12 pack of 16 oz almost every time, sometimes I get 14!