Imperial Stout Water/Mash - Holding Roasted Grains and Proper pH Management Question

[najohns]

So, I was hoping someone might be able to help me with a stout water profile and mash schedule. I want to separate my roasted grains and hold them until vorlauf, but it appears that many people who do this do not properly adjust for proper pH in the mash and after adding back the roasted grains when they build their water profiles. I’d like the take the following grain bill and split it up, where I mash the MO, C77 and C40 at pH 5.4 (using 5.7 gallons distilled water and 1.7 mls lactic acid to hit pH 5.4… as per Bru’n Water), then add all of the dark / roasted grains at vorlauf, along with my final water adjustments of an additional 2.6 g gypsum, 0.6 g NaCl, 1.4 g baking soda, 2.3 g CaCl2 and 1.4 g pickling lime to achieve a final water profile of:

92 ppm Ca
28 ppm Na
66 ppm SO4
67 ppm Cl
101 ppm bicarb
RA 18 ppm

pH 5.4

I’m hoping this will allow me to avoid some of those grainy / tannic flavors from mashing the roasted grains, while keeping my mash pH and final pH in a reasonable range for an imperial stout. My questions are, will mashing the MO, C77 and C40 with only a simple acid addition (and my grains) to hit pH 5.4 affect the sacch efficiency or the beer flavor? Will the grain bill provide enough buffering capacity in the mash to maintain a mash pH of 5.4? Do amylase enzymes need the additional ions / co-factors usually provided in non-distilled of regular water to catalyze conversion efficiently?

OG = 1.095
3 gallon batch

8.9 oz black patent 538L 3.9%
13.6 oz black barley 750L 6%
5.2 oz brown malt 65L 2.3%
1 lbs 0.6 oz beet sugar 7.3 %
5.2oz crystal 40 2.3%
4.1 oz crystal dark 77L 1.8%
8.9 oz chocolate 350L 3.9%
10 lbs 4.6 oz Maris Otter 3.5L 72.5%

Thanks guys.

 

[mabrungard]

The off flavors you mention are not typically the result of mashing roast grains with the rest of the grist. Its more typically the result of an overly low kettle wort pH due to the mashing water not having enough alkalinity. Millions of brewers before you have mashed all the grains together when their water supply has some alkalinity and the results are typically good, if not great.

To my knowledge, Boston water is not that bad and resorting to DI water may not be necessary. But if that is your preference, just mashing everything together in water that has the correct alkalinity level to produce a pH in the 5.4 to 5.6 range should provide you with good beer. I and others have found that targeting mash pH in the 5.5 to 5.6 range does help the roast flavor smooth out and become richer.

While reserving the roast from the main mash does work to keep that pH in a proper range when working with low alkalinity water, the kettle wort pH can be too low, as you know. Your attempt to correct that is likely to work, but it is likely more work and I don't think its necessary. Mashing all the grains in the proper mashing water does work well and should not produce the off flavors you are concerned with.

 

[cannman]

My stouts tend to run low on PH using about 100ppm local water (Ward Labs deconstructed). A little calcium carbonate AS NEEDED on top of your water profile additions during your mash should fix you right to your 5.4 range. easy as pie

FWIW

Take a ph Reading 15 min into your mash before adjusting and make sure all other water additions are in by dough in.

 

[najohns]

Thanks for the help. I definitely don't want to make extra work for myself, as this is already a double mash brew.

I use DI water simply to try to have complete control of the brew (ie trying to learn all aspects). I will mash it all together. I've heard that tannic character and harshness is more a function of ph than when you add the grains, which makes perfect sense. I was trying to be overly cautious this go around.

I'm targeting ph 5.4, due to some error I have not been able to nail down in a previous brews ph, when using average lovibond ratings for my grist and weighing all grains and water addition using analytical balances / graduated cylinders. My last brew crept to 5.8 or above, as per my bench top ph meter. I can't explain why, other than a calibration error somewhere, so I'm aiming a bit lower this time, just in case.

 

[cooper]

If you don't have an aversion to using acid, have you thought about using lactic or phosphoric acid to bring all of your brewing water down to a pH of 5.5 and then start your mash from there? The dark grains will bring down the mash pH some if you mash everything together but I'm not sure exactly how much or you could add your dark grains in at vorlauf if you wanted. That way you'll definitely be sparging with water that has a pH at 5.5.

 

[najohns]

This is a no sparge recipe, so no worries on the sparge ph.

 

[najohns]

So, I brewed the above beer and I took my final gravity reading last night. Mash pH ended up stabilizing at about 5.3 - 5.4. It sat in primary for 3 weeks. It tastes quite flat and has a very bitter, minerally flavor. it's not great. Did I over do it on the salt additions? I'm cold crashing now, in hopes it is just a young, yeasty flavor and not the water.

 

[cooper]

I would taste it again after you've carbed it up. The OG was 1.095 so that's a pretty big beer and its still pretty young and flat.

 

[m00ps]

big stouts like that usually need at least a month in the bottle to condition

 

[najohns]

I totally agree, it is very young, but the way this one sits on the palette has me concerned. It is overly bitter and lingers, with that sharp feeling on the tongue, like alka seltzer, and flat (by flat, I mean dull and a bit lifeless). My pH was fine, so high pH shouldn't be the dull factor, but the sharp, lingering bitter mineral taste could be water. I was just wondering if my salt additions seemed too high?

 

[cooper]

I'm not sure, you used:
2.6 g gypsum
0.6 g NaCl
1.4 g baking soda
2.3 g CaCl2
1.4 g pickling lime

The only thing I've ever used is either Gypsum (Sulphate for hops character) or CaCl2 (Chloride to accentuate malty character), and that's only a tsp in the mash and I'm usually well over 50 ppm of Ca.

Would you be able to brew it again and cut down on the mineral additions to maybe just CaCl2?

 

[najohns]

As long as that addition alone puts the pH at 5.2-5.5, from di water, which I don't think it would. That's the problem... some of my additions are simply for taste, but the baking soda and pickling lime provided the alkalinity. I'm just not sure if I should have backed down on the overall mineral additions... like cut the roughly in half and targeted pH 5.5 -5.5.