Below is my water report: Ca - 60, Mg - 22, Na - 84, CI - 86, SO4 - 190 HCO3 - 134 I am cutting my water with 50% RO. To achieve a 5.37 mash ph I would need to add 10 grams of gypsum and 6 ml of lactic acid. The grain bill is 12 lbs of base malts and 1 lb of flaked wheat. The style is an ipa with a projected ABV of 6.8%. The final numbers come out to: Ca - 106, Mg - 11, Na - 42, NaCi - 43, NaHCO - 278, HCO3 - 67, chloride to sulfate ratio = .15. My question is that too much gypsum or lactic acid for 5 gallon batch with 13 lbs of grain? Should I increase the gypsum and decrease the acid or vice versa? Should I add more RO water to reduce the amount of additions? If I increase the RO water my magnesium becomes really low. Or that looks good? I've been brewing 3 - 4 gallon batchs with equal additions of gypsum to lactic to achieve silimar results and the beers have been good. The last ipa I brewed had 6.5g of gypsum and 3 ml of lactic acid for a 3.5 gallon batch with 8.5 lbs of base malts and .5 lb flaked wheat. However, it seems like this recipe requires significant amount of additions to lower the ph and I am concerned it will give it a mineral and or tart flavor.
Your final numbers have some odd looking ions (hey, I had an odd post today too). If your SO4 is 278 ppm, that is fine for the flavor ion. Use more acid to hit mash pH, rather than cranking SO4 higher to add more Ca to drop pH. Another strategy would be to use 3/4 RO water to drop the HCO3 more, then you need less Ca, MG, and acid to drop the pH, as you have less Alkaliniy to start.
I always have odd posts so I am used to it. So I put NaHCO3 instead if SO4. I think you figured that out. I was tinkering with more RO but then my Mg drops to 9 or 8, which below the desired minimum of 10. Also, I thought for an ipa SO4 can as high as 300? Is there any known level that one could taste acid or mineral? I heard there is a threshold when using acid malt, but not sure if that's the same for lactic acid.
Mg levels are not that important, you get a lot from the malt. If you increase the SO4 to 300, you won't add much Ca, so you pH only goes down very little. I for get what the upper range is for lactic acid, I don't think you are there. Disclaimer - I use Phosphoric acid, so I don't know lactic numbers that well.
