After all the discussion about alkalinity in the pickling lime thread, I was playing around with some recipes in Bru’n Water today. I created a basic test recipe for a beer of about 50 SRM:
I added salts to get my water to approximate the “black malty” profile, and the mash pH estimate came out to be 5.5. Great! But then I scaled the grain and water 3x for a 15 gallon recipe, and the pH estimate changed to 5.3. Huh??
Am I doing something wrong? I can’t think of any reason that the results aren’t independent of batch size. The grain and water were both scaled proportionally, and salt additions scale automatically since they are written in g/gal.
No, its an error in the program and the way things are calculated on the mash acidification sheet. I noticed it a couple of weeks ago. The pH is correlated to the milliequivalents of Net Mash Acidity. That works most of the time, but that approach breaks down as the batch size deviates from the typical homebrew batch size. The proper approach is to normalize the acidity into milliequivalents per liter. That way the size of batch never influences the result.
I’ve uploaded an important update to Bru’n Water that corrects that error and provides significant improvements in the User Interface. Do try it out. The pH estimation algorthym has also been tightened a bit, based on continued data collection from users. So there should typically be a slight increase in the pH estimated in version 1.12 compared to version 1.10. Those brewers that were brewing batches much larger than the typical 5 gal batch may see more substantial pH difference.
My apologies for not recognizing this error sooner.
Hey Martin
Thanks for the update. I’m trying to add some grains but I can’t select a different Grain Type from the dropdown, it complains that the cell is protected or read only.
+1 I really don’t understand water chemistry, but I had been using every method/program previously available to try and get a handle on it. Bru’n water has given me the best tasting results and the understanding water portion has given me a lot more confidence about making these adjustments. Thank you Martin for sharing your work on a subject elusive to many of us.
True! I’ve used Brun Water for over a year in tandem with Kai’s spreadsheet, for beers paler than amber, starting with distilled water and adding stuff in. Brunwater always gave me a predicted pH of 5.2 whenever I did a 10 gal batch, while Kai’s mostly predicted (pretty accurately) in the 5.4 -5.6 range (of course recipe/batch-dependent). Today I download Martin’s fix and worked up the water additions for a Jever-style pils recipe that I’ve brewed 3 times before, and Brunwater now predicts 5.5, in line with Kai’s predicted 5.46.
