Oatmeal Stout additions

[ggriffi]

For my next brew session I want to start the deep dive into water and homebrewing but I do have some questions. These numbers are for an Oatmeal Stout I am planning on doing.

Here are my numbers from Wards.

pH 7.8
Total Dissolved Solids (TDS) Est, ppm 462
Electrical Conductivity, mmho/cm 0.77
Cations / Anions, me/L 8.3 / 7.9
ppm
Sodium, Na 57
Potassium, K 7
Calcium, Ca 63
Magnesium, Mg 30
Total Hardness, CaCO3 283
Nitrate, NO3-N 0.2 (SAFE)
Sulfate, SO4-S 20
Chloride, Cl 40
Carbonate, CO3 < 1.0
Bicarbonate, HCO3 336
Total Alkalinity, CaCO3 277
Total Phosphorus, P < 0.01
Total Iron, Fe 0.05
"<" - Not Detected / Below


So after input to Bru n' Water and playing around for a bit this is what I got? 1st attachment (OS1) and the additions 2nd attachment (OS2).

Being a noob at this water thing, I don't understand a few things.

1) IF, these numbers are in the ballpark, when should I make these additions? When should I add the CaCl
before or after mash? For the lactic acid I thought that I read where @ajdelange recommended half the acid and then take a measurement to see where I'm at before adding the other half (or not).

2) If the samples need to be cooled to get the correct reading and I am waiting on those to make my additions, can I go ahead start up the kettle for boil or do I need to wait until I get the numbers?

Sorry for the noob questions and if they have been answered before, but my head is swimming with all the info out there.

 

[mabrungard]

While your diluted water still contains a significant alkalinity content, the low calcium content will prevent it from decarbonating when its heated. If you had been using your raw undiluted water, heating would cause a significant amount of the alkalinity to have been driven off. Since your acid addition was calculated based on the unheated water's alkalinity, you would overdose your heated water with acid in that case. But again, your diluted water won't suffer from that problem. So you can actually add your acid and minerals to the heated or cool diluted water.

To be safe, I recommend that brewers add their acid to their unheated water to avoid the issue mentioned above.

 

[ggriffi]

Thanks Martin!