« on: July 03, 2016, 09:49:14 AM »
Sometime soon I will be using RO water and additions for a half-batch (3 gal) of Gordon Strong's Landlord Tribute recipe from Modern Homebrew recipes. It's my first effort at using RO water + additions. The LHBS had 25% phosphoric acid so that's what I bought. My grain bill will be 5 lbs Golden Promise and 1.5 oz debittered black malt.
For a six-gallon batch, Gordon specifies RO water treated with 1/4 tsp 10% phosphoric acid per five gallons, plus 1 tsp CaCl2 in mash, 0.5 tsp CaCO3 in boil.
Working with Bru'n Water, to get my mash water into the "green" (fyi I typically don't sparge) requires I push up the 25% phosphoric acid to at least 1.05 ml/gallon, yielding an estimated mash ph of 5.5. For a 3-gallon batch I mash with around 5 gallons of water, so that would translate to just a little over 5ml phosphoric acid (about 1 tsp). That's a lot more, proportionately, than Gordon recommends. Is that a bad thing?
Adding .25 calcium chloride per gallon to the mash works out ok -- the mash ph stays the same. But adding anything higher than .01 gram/gallon chalk to the boil (with "add hardness minerals to kettle" checked) pushes the estimated ph into the upper limits (orange) range. I am thinking that for this recipe this range may make sense, because the recipe specifies a "minerally" quality--does that seem right?
I'm in no rush, just trying to understand a) this recipe and b) water treatment and c) Bru'n Water. I plan to brew the recipe this weekend with my current process -- using filtered fridge water, no treatment -- then brew it again in a couple of weeks with treated RO water.
I just passed two major milestones in my graduate studies, so I am also thinking "go on, treat yourself to a ph meter." It seems a little odd to make a lot of adjustments and not measure as I go.