HOW MUCH calcium hydroxide?!?

[JonM]

So I'm having yet another mash pH puzzle. I'm brewing a dunkelweizen the following:

5.5 gallon batch

5.5 lbs Dark Munich - 9 L
5.5 lbs dark wheat - 7.2 L
0.2 lbs Dehusked Carafa III - 520L

I have 1.5 qts/lb (although in a mistake my test mash used closer to 1.75 qts/lb)

6 g of calcium chloride

Brewers Friend predicted a mash pH of 4.93. Test mash was closer to 5.02/5.03. (I ran the same figures with the 1.75 qts/lb and Brewers Friend's predicted mash pH was pretty close to the 1.5 qts/lb)

Anyway, Brewers Friend is now telling me I'd need something like 14 grams of calcium hydroxide to get about 5.4 mash pH, or some similarly large combo of baking soda and calcium hydroxide. Can that be right? I'd wind up with 300 mg/L of calcium using just calcium hydroxide.

Unfortunately, the grains are all mixed so I can't leave the Carafa out of the mash.

Thanks for the help, folks!

 

[ScrewyBrewer]

What was the temperature of your 5.02 pH mash sample? What were the calculated Mg, Ca, Na, Cl and SO4 ppm values for your recipe, using Dark Munich, Dark Wheat and Dehusked Carafa III? Don't forget to factor in the maltster's DI pH value of their malts too.

Discrepancies between calculated and actual mash pH values many times can be traced back to having input incorrect DI pH values for the malts in the recipe.

 

[JonM]

I'm not so much concerned with the discrepancy as I am about the way low pH. It's funny because I've made this recipe before and it's worked out fine with a mash pH of 5.4 with no alkali stuff added.

And the water is RO with the CaCl, so it was about 50 mg/L calcium and whatever chloride came with it.

 

[JonM]

I think if I add 2 g of baking soda and 2, maybe 3 grams of calcium hydroxide, that should get mash pH into a good range and not overload the calcium and only get about 18 mg/L sodium.

Next time I leave the Carafa out of the mash. Brewers Friend says if that wasn't in the mash, the pH would be fine. Live and learn.

 

[trentm]

This had me curious so I ran your numbers through Bru'n Water. Assuming you are starting with RO water, with your grain bill and 6g of CaCl2 Bru'n water says you should need 5.5g of calcium hydroxide to hit a mash pH of 5.4. It also says the 6g of CaCl2 is providing 206 ppm of chloride and increasing the calcium by 115 ppm. That's dragging down your pH a bit and adding to the already high calcium level. I know you want a high level of Chloride to bring out the malt flavors but perhaps consider lowering your CaCl2 and adding a little salt. Perhaps a chloride level of 80 -100 ppm would still get you the malt profile you're looking for. This would let you get by with less calcium hydroxide.

 

[JonM]

I wound up using 3 g calcium hydroxide and 2g baking sofa. The Ca and Na numbers were reasonable. Mash pH was 5.62ish.

Bah. My next batch is a schwartzbier. I'm cold steeping the dark grains and leaving them the hell out of the mash.