Modifying recipes for process?

[Muskietooth]

Newbie question - I want to make a half batch of a recipe I found. The recipe is all grain and I want to do it through BIAB.
1.Can I half everything or do you not half the hop additions?
2. Do all grain portions change for BIAB? (Specifically for the mash).

 

[Sam_92]

You would half everything to do a half batch.

The only difference wouldn't be biab itself per sé but your efficiency on your system. The same applies to any type of all grain brewing, I target 75% mash efficiency and I get real close almost every time.

 

[IslandLizard]

You basically can cut everything in half...

The only thing that needs a little more attention is your boil off volume. Boil off volume tends to be more or less the same, say 1 gallon, whether you boil 7 gallons or 4 gallons. You'd end up with 6 gallons and 3 gallons (1/2 of 6 gallons), respectively.

Boil off depends on your heat source and kettle too, so if you change those, you may need to correct.

Grain portions for a recipe should be the same whether you brew BIAB or conventional (separate mash tun). You may get a little higher mash efficiency if you mill finer for your BIAB than the original recipe. Most recipes are based on 75% mash efficiency. With BIAB you should be able to get 80-85 % with finer milled grain, and a small sparge. Hold some (say a gallon) of the calculated mash water back for the sparge.

For a sparge dunk the bag in a bucket on the side, after the main mash is done and the bag has dripped/squeezed out. Then add the wort from the sparge bucket to your kettle.

 

[jdauria]

Just an FYI, just because you are doing BIAB, it's still all grain brewing, just a different method vs the mash tun/brew kettle version of all grain.