Monday, March 2, 2015

Utilizing Phophoric Acid for Water pH Adjustment

Yesterday was another brew day. I'm trying to dial in my water adjustments for pale beers, specifically IPAs, so that is what I brewed once again. I focused on adjusting all my water and watching my pH for sparge and mash.

I started out by collecting 9 gallons of water early in the morning, adding 1/2 of a campden tablet and checking the starting pH. My meter was spot on at 7.7 with my last water analysis from less then a month ago

I used the Bru'n Water spreadsheet to calculate the amount of phosphoric acid I would need to bring my water down to a pH of 5.5. The spreadsheet indicated to add around 130 ml which I thought was a bit high. Thankfully for once I had the common sense (and soberness) not to just blindly trust the figure on the page.

I initially added 30 ml of a 10% solution of phosphoric acid to the 9 gallons of water I collected. I waited 15 minutes then checked my pH again and I was down to 6.5.  I repeated this step again except that I only added 15 ml then next time around. The result was a pH of 5.9. I added another 15 ml and the result was a pH of 5.3 which I should have known considering the changes the pH had taken in the last two rounds. To fix the over adjustment I added tap water at 4 cup increments and re-measured between each addition until I reached my 5.5 pH target after 12 cups.

So at that point I had 9.75 gallons of water adjusted with phosphoric acid to a pH of 5.5. I Collected 4.6 gallons into my mash tun for a 0.4 thickness mash with 11.5lbs of grain. After doughing in I waited 15 minutes then checked my pH which nailed my target mash pH at 5.2. The last time I brewed this IPA, I brewed it without the acid adjustment and simply added 10 grams of gypsum to gain a Burton on Trent like water profile. That time my pH was 5.8 so this is the first pale beer I have brewed where the mash pH landed in the commonly targeted 5.2-5.5 range. 

I checked my pH twice more throughout the mash and it held steady at 5.2. There are arguments both ways that you should/should not acidify your water to bring the mash pH into a target range, I simply decided to try it for myself and record the results here.

This beer is now fermenting in two buckets, in one I pitched a typical American ale use Safale US-05 and in the other I pitched an English ale yeast Safale US-04. This was just for fun so I could compare how the exact same wort would taste pitching two yeasts that I use frequently. Although I usually save the US-04 for my stouts so this should be interesting.

I will post again with the comparison of acid adjusted and non-adjusted water and another for the comparison in yeast strains. I’ll probably also eek another post out of this batch because I only added 7 grams of gypsum this time because the 10 grams in the last batch came out a tad salty and also 7 grams puts me in the 1:3 ratio of chloride to sulfate.

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