Brewer's Friend confusion

[tempestam83]

I have a recipe inputted using Brewer's Friend and am a little confused with the batch size and boil size entry.

I'm aiming for a 5-gallon batch BIAB with 9 lb grain and 3 lb. DME.

I'm mashing in 3-gallon of water with 1-gallon sparge and boiling 4 gallons.

I entered 5 gallons for batch size and 4 gallons for boil size. Am I correct to assume the different between those numbers will be the top off water?

 

[m00ps]

all that should really matter in terms of calculated the pre-pitching OG is the batch size. But you boil size cant be smaller than your batch size. You LOSE water to evaporation during the boil. Standard would be about 6-6.5gal pre boil, 5-5.5gal post boil

if you start with 4gal before the boil, and dont add water during (in which case you should probably boil longer to account for heat reduction) youll probably have 3gal going into the fermentor

 

[tempestam83]

My problem is I only have an 18 quart kettle for now. What are your thoughts on keeping a separate pot with boiling water and adding that throughout the boil what would that do?

 

[CUrchin]

I don't use BF, but I'd calculate it as though you were doing it as a full batch with top up including the grain and DME. I would BIAB the grain- At 9 lbs in a 18 quart pot I'd probably plan on doing a pour over or dunk sparge to get as much water in there as possible but still have a little room to prevent boil over (maybe leave yourself a gallon of space and the be very, very careful at hot break to not have a boil over, spray bottle or kill the heat). I'd hop per the normal schedule, and then throw in the DME at the end. Chill, transfer to primary and then top up.

The concern I would have would be that your grain makes up most of your intended gravity, but your going to probably top up about half the batch. I haven't done any numbers and I don't know what you are making, but your efficiency might come in lower than you hope with 9 lbs in a 18 quart pot, and the top up water will dilute it further. It probably will turn out okay, but you might want to consider getting more of your gravity from DME (say half), doing a smaller batch size and just do BIAB, or doing two pot BIAB. There is no reason you have to do a 5 gallon batch. I am making some assumptions based on my experience doing 3 gallon batches in a 5 gallon pot with what I write here. Your results may vary, and hopefully for the better. What ever you do I hope it works out.