So I'm brewing my first all grain witbier and I want to do a protein rest. I am just slightly confused on the water volumes that Beersmith is giving me. When I just use single infusion batch sparge, my mash in volume is 25 quarts but when I change it to double infusion it comes out to 33 quarts between the protein and sac rest. What am I missing?
IMO, I'd just skip the P-rest. More negatives than positives, Unless you are using an undermodified base malt. Generally, most base malt's today are nicely modified and are capable of converting their own weight in unmalted grains. In some cases it can even hurt head retention.
It's giving you more qts to calculate in the amount of boiling water needed to bring your mash up from protein rest temp to saccharification rest temp. Sparge volume will just be less. Ie. if I do a ferulic acid rest at 114 F with 1.25 qt/lb with a 10 lb grist, I'll be 12.5 qts in to hit 114. I'll need an additional X qts of boiling water to bring my mash temp up 30+ degrees for sacch rest.
Try this Mash Calculator. If you're going to do multiple rests, adjust the water grain ratio down to something like 1.10 for the first infusion. This will rise gradually as you add smaller quantities of boiling water to achieve you subsequent rest temps, but it shouldn't get to soupy if you start a little on the dry side.
This is along the lines of what you want to do. For Wit you will want to do this, as it helps the lauter. The advice to not do it is fine for most beers, but with a Wit with unmalted wheat it will help the lauter. One should read "Brewing with Wheat" by Hieronymus to see the step mash schedules used by Witbeer breweries.
