[Mods, I've started this thread here rather than clutter up the 'my first post' thread.]
Invariably questions about stovetop batch size and brewlength come up. Here's one recent question to start the ball rolling.
This site has been great for researching the BIAB technique. I'm trying to work out a recipe to try (thinking about the APA listed here) that fits my equipment. Currently I have a 20L pot to boil in. Any rough ideas on how large of a batch I could make?
Yep CSchenk, as hashie relates, the cheap and plentiful 19L stockpot is my main weapon and Maxi-BIAB
is the way I get bigger batches out of it (not sure if that's what you're after though?). The method has a few sneaky clever tricks which makes life a bit easier as well, so I do recommend it, but maybe try Mini-BIAB
first to get a more wholesome BIAB experience, if you do that you should be able to get 13 or 14L per batch in that stockpot.
Now, with Maxi-BIAB you should be able to brew 23- 25L batches with relative ease
, I do that pretty much all of the time, I've not done more than 25L but I don't have too many doubts about being able to do 30L of lower- strength beer (say around 3- 4% abv). The main reason I haven't done the bigger run is that I don't actually have a fermenter big enough, so it is pointless really unless I had a use for an extra 5L of wort (haven't until now).
Post- boil dilution is where the extra volume is made up, because we're adding just plain water obviously the wort (unfermented beer) is stronger than usual, but this doesn't cause any real problems and it is just a straight concentration- volume conversion. I usually mash 4.0 to 4.5kg of grain per batch, it generally yields 17L of about 1.070, so with a target gravity of 1.048, the maths go like this:
Actual SG / Target SG * Actual Volume , so 70 / 48 * 17L = 24.8L diluted, so the water added is 24.8 - 17 = 7.8L
As an aside, that example was a very efficient mash from 4.0kg base malt, 0.17kg specialty malt and 0.2kg dextrose, the dex is to style in a UK Bitter but brewing dextrose/ sugar- friendly styles is another helpful way to ensure volume and gravity targets are met. Also the sophisticated (
) method that I use for filtering the wort (a simple kitchen sieve!
) is about as efficient as it can get, so just about all of that 17L of concentrated wort is captured in the fermenter, this also helps keep overall efficiency high and the desired batch size achievable.
Give me a beer and I will move the world. Archimedes