Topping off boil kettle for 10 gallon batch?

Hey guys,

I normally brew 5 gallon BIAB full volume, no sparge, mashing in a 10 gallon cooler and boiling in my 15 gallon kettle.

I need to brew 10 gallons of a 1.050 OG lager for a party, so the way I see it I have 3 options:

  • Brew two separate batches

  • Use my boil kettle as the mashtun, mashing with the full volume of water (I’ve never mashed in my boil kettle and am worried about holding temps)

  • Mash in my 10 gallon cooler at 1.5qt/lb and topping off the boil kettle with water

Option three is what I’m leaning towards. Any reason topping off the boil kettle with several gallons of water to get the correct pre-boil gravity and volume is a bad idea?

Thanks,
g

I don’t see any problem with it and have done something similar myself several times. Just be sure you stir everything really well after adding the top-up water before you take a sample to measure the gravity.

how many lbs of grain are you using for this recipe?

I always mash in my kettle. Just wrap a blanket around it and you’ll be fine. I’m in PA and brew in my garage like that all the time. Temps are only critical for the first 20 mins or so.

How about sparging?

Yeah, why not go with option 3 and sparge?

Unless I’m missing something, why can’t you just mash in your 10 gal cooler and batch or fly sparge?

I’d avoid topping off with that much water. It will dilute not just the sugar content but also the flavor and color, so you might not get your desired final product despite hitting your numbers.

You’ll also use less grain if you sparge, in addition to the aforementioned advantages.

#3 + sparge

Agreed. 19 lb grist with 7 gal infusion and 7 gal single batch sparge will easily fit in the cooler, should be easy to do with your current BIAB equipment and procedures, and will give you 11 gal of wort at ~1.050 with full conversion.