# One Gallon BIAB Setup Questions

Long time beer drinker, first time brewer.

I am eventually, soon, going to go all grain brewing and plan on one gallon batches. I MAY bump up to 3 gallon batches but 5 gallon is out of the question. I have done research between forums and friend brewers and have come to a mostly good idea on the setup I need to do BIAB but I want to hear from the people on here.

Recipes are pretty easy when it comes to the conversion, just scale it down to the one gallon. What I have had trouble with is determining the amount of water to use and boil and rest times. My initial thought is use the boil and rest times from the 3 gallon recipe kits from NB on my similar style recipes. The big question that I have not been able to answer is how much water do I use?

Do I use roughly use 2 - 2.5 gallons to make my mash and just add water to bring me to the desired 1.5 gallons? I roughly loose 0.5 gallons per hour when heating and boil so with mashing and boiling I figure I would loose a gallon of water. I know it seems like a lot of loss but my stove does not heat up quickly so I loose a lot to evaporation.

Does this seem acceptable for one gallon BIAB? Thoughts are greatly appreciated.

There is no one answer fits all because of your set up, including whether you squeeze the bag or not. With a 1 gallon BIAB, squeezing might yield 15% if your volume. Also grain bill will vary the amount of wort required.

All grain is a trial and error, take notes and adjust process.

Simple way to calculate water needed is to start with the desired volume into the fermenter, then add the water lost to evaporation during the boil, then divide the weight of grain by 8 to convert to gallons lost to absorption (grain absorbs 0.125 gals per lb). So if you’re doing a one gallon recipe with 0.5 gallons per hour boiloff, a 90-min boil, and 4 lbs of grain, you would need 1 + 0.5 x 1.5 + 4/8 = 2.25 gallons in the mash. With a little over 2 qts per lb, it’s going to be a thin mash, which is usually a good thing.

If you want to sparge, keep some of the water out of the mash, heat on the side, and when you pull the grain bag out of the kettle pour the hot water through the grain to rinse.

Over this past winter I’ve brewed 7 one gallon AG test batches, and from looking back on through my log I’d say your 2-2.5 gallons used for your mash should work great.

I usually use about 2-2.25 gallons for my mash, and this is the only time I add water. With loss to grain absorption(about 1.5-2qts) my pre-boil volume is consistently ending up around 1.8-2 gallons. After an hour long boil with my large stovetop burner on high, I end up with a gallon lost to evaporation. From there a little(1 cup) is lost to trub, and I’m ready to pitch with 0.8-1 gallon of wort.

I did brew a barley wine(5lbs barley) with 2.5 gallons of water for the mash, and that was almost too much water. I had to boil an extra fifteen minutes to hit my target post mash/boil volume of 0.8-1 gallon wort.

Thanks for the input!

I figured most of it would be trial and error and learning what works and what I like but it is good to know I was heading in the right direction.

Can’t wait to give it a go!

:cheers: