I brewed a NB Smashing Pumpkin BIAB a couple weeks ago and noticed that I only got about a gallon and a half of what was supposed to be a 3 gallon batch. I noticed in the instructions it called for 4.5 gallons of water… I brewed an Irish Red BIAB the week before and it called for 5.5 gallons of water to start out with… I’m very new to brewing and do not understand everything. I followed the instructions to the letter, so I don’t understand why I came out so short? Like I said, I’m new so please go easy me, lol. Thanks so much. Should I have topped that up to 3 gallons after the boil? I took the OG and it was correct per the instructions, just extremely short of wort. Any tips would be appreciated. By the way, I mashed in a cooler and I may have lost 2 degrees in the 75 minutes.
I do add more water.taking in acount the boil of the water so five gal for example i do add one gal more water so at the end i have five gal of wort
I’ve not done either of these kits BIAB but I’ve done Smashing Pumpkin several times and it’s an awesome beer! I’m not quite sure why the SP calls for 4.5 gallons of water and the Irish Red calls for 5.5 on the kit instructions. The SP has 1.5 lbs more grain than the Irish Red so that will absorb some more water, but not much. On my system, I calculate grain absorption at .12 gal/lb so a 7.25 lb recipe should absorb just shy of 1 gallon of water.
If you boiled for an hour you can estimate roughly 1 gallon loss to evaporation (this depends on your setup). Both recipes say you should have roughly 4 gallons before starting your boil so I assume the 5.5 would be a better starting point. Maybe one of the more experienced BIAB guys can get you a better answer for that.
Typically when I was doing partial boils, once you chilled your wort down to yeast pitching temperature, I would add some water to the fermentor to get to your target volume before you pitch the yeast.
Thanks for the quick reply’s. If I brew this one again, I’ll start with 5.5 gallons. I’m curious how it’s going to turn out since I lost so much water and I didn’t add any.
Most of my 3 gallon biab batches start with 5 gallons…lose a half to 3/4 gallon to absorption…and then boil off a gallon…typically a little over 3G into fermenter and bottle a little under 3G.