I would add salts to the 20 gal of HLT water to create the water profile you want and then use only the amount of water you need for wort production. Waste the unused water.
Its important to understand that the alkalinity (bicarbonate content) of mashing and sparging water can be quite different. You may have differing acid requirements for each brewing component.
Unfortunately, I'm not familiar with the Kindle Fire. I don't expect that it has the capability to run Excel or LibreOffice...but I could be wrong.
Martin,
So are you saying to treat it (on the software side) as a no sparge and then split the water into two equal proportions to fly sparge with?
Sent from my iPhone using Tapatalk
That's my understanding of what he wrote, however I don't think that's a reasonable solution here since you'll only be mashing with a portion of that water and the grain will greatly affect the mash pH based on the grist:water ratio. Hmmm...
Loosely based on what Martin said I’m wondering if I can treat my mash water in the MT and then drain the HLT the to the correct amount of sparge water and treat that amount while it remains in the HLT after mashout temps have been reached. Then, use that to sparge. My only hang ups are calculating the correct amount of sparge water based on the losses to the herms coil and the bottom of the HLT - roughly 3/4 of a gallon.
Sent from my iPhone using Tapatalk