Single Infusion Batch Sparge – How to handle this line up?

I have only done a couple AG batches, but none that called for “mash at 122 for 15 minutes, then raise the temperature over the next 15 minutes to 154 and hold until conversion is complete.”

My question is: I use a 10 gallon cooler and batch sparge. Since I can’t fire heat under the cooler, what is the best way to handle this mash? Add additional water to bring to 154?

Recipe is a 5 gallon batch, witbier. I am following the recipe from Brewing Classic Styles.

5.5 lbs. Pilsner
5 lbs. Flaked wheat
1.1 lbs. Flaked Oats
.25 lbs. Munich
.5 lbs. Rice hulls
1.2 oz Hallertau (60 min)
Citrus Zest 1.5 oz
Crushed coriander .04 oz
Chamomile Flowers .03
WLP400 Belgian Wit Ale

I am a relatively new AG brewer and looking to learn. Thanks for the feedback.

Yes, add additional hot water to bring it up to 154. I would use a thicker mash for the rest at 122 so when you reach your main mash temp, the mash isn't overly thin.

They are doing the lower rest for the flaked oats and wheat.

I cannot comment on whether that's actually necessary though.

Assuming you do the stepped mash, I really recommend some brewing software. Promash in trial mode will allow you to figure out how much water to add to raise the temperature, and you will indeed start with a pretty thick mash , so that you've got room to add all the water for the stepped mash schedule without getting too thin/throwing off pH, etc, since you can't direct fire your MLT.

here's a free online calculator to help: http://www.tastybrew.com/calculators/infusion.html

there are a couple ways to do it, and all but a RIMS/HERMS are kind of a pain. when i need to step like this, what i do is simple (but a bit laborious).

first, get a 1300 watt hot plate.
second, after a few minutes at 122F, drain 1 gallon of wort into a kettle on the hot plate and heat to 165F. add back to grain bed.
third, gently stir for 20-30 seconds, and repeat.

this will favor a drier beer, but will not cause any caramelization or excess melanoidens. if you want a maltier, chewier beer (like many scottish beers) increase the temperature of the portion of wort that you are heating up.

oh yeah, this method will only work for smaller batches given the limited power of a hotplate. if this were a 10 gallon batch, you would probably need 2000 watts to raise it that fast.

A wit is a bit out of season but sure why not. Mash at about .75 quarts per pound. Strike temp will near 134f. Hold at 122 for 20 min and add enough boiling water to reach the next rest temp.