For any of those that use Brun water. I've found that my use of the lactic acid concentration does not work for some reason. If I set to 88% (standard concentration), it underpredicts the amount of acid I need - or, overpredicts the impact on pH. If I set to 18%, it more closely calculates the amount of acid needed and its impact on pH. Anyone else had this issue before? I've checked my water report to make I'm inputting correctly and everything seems to be matching up ok. Also, 88% does seem to work closely (but not perfectly) for the sparge acidification sheet.
So is your ph not getting into the correct range in bru n water or are your actual ph readings on brew day off? I use bru n water on all my beers and my numbers are always good on the spreadsheet and I've actually never checked my actual ph to double check.
When did Martin send you the latest update? Mine has an _3 on the end of the filename. I got an update in mid-July (_2) that seemed off in some ways. Martin sent another one (_3) shortly thereafter (late July) that seemed more better.
I just went to the site and downloaded ver16b. I was using ver 12. The results didn't change much. As an example. For a batch that I made yesterday. Brun water predicts that my pH should have been 4.9 to 5.0. It was actually 5.4-5.5. So, my mash pH numbers are fine. They are just not what Brun water predicts. I suspect this has something to do with the mash acid contribution. Before you ask. I take my sample in the first 10-15 minutes after the infusion is done. I mix the mash, then sample from the top with as much liquid (non grains) as I can get. I cool to ~ 77 deg F before measurement. I use a pH meter calibrated with pH 4 and 7 standard calibration buffers. Therefore - I trust the meter. As I said, I double checked my water report, everything seems to be in order.
Hmm? Bru n water is always predicting mine in the 5.2-5.5 range after adjustments. So maybe I'm actually nearing an actual ph of 6. Now i have to ask Santa for a ph meter. Dang it! Edit* I rarely need to add lactic acid to my mash to get my predicted ph in a good range per bru n water.
Again - I suspect if you aren't acidifying your mash with acid, you're probably okay. The addition of acids has a strong impact on mash pH in Brun water.
I have studied Brun Water (as well as EZ Water and Kaiser Water) in quite some detail, so I may be able to shed some light on this topic. When it comes to 88% lactic acid, Brun Water does a good job at calculating the contribution of the acid to the residual alkalinity (RA) of the strike water. However, the relationship between RA and the change in pH in Brun Water is (in my opinion) significantly larger than it should be. That is, the slope of pH versus RA is too large. I base this statement on my analysis of Kai Troester's data on mash pH. There is a problem with Brun Water's lactic acid calculations, but I don't think this is the source of your problem. This problem has to do with the fact that Brun Water does not account for changes in acid density with changes in acid concentration. The result of this is that at concentratoins less than 88% Brun Water overestimates the acid's contribution to RA. Further discussion of Brun Water (as well as EZ Water and Kaiser Water) can be found here and here. Based on an extensive analysis of Kai Troester's data, a new spreadsheet has been developed to calculate mash pH. For comparison, for a mash of 10 lbs of pilsner malt at 1.5 qt/lb to which 50 ppm Ca and 3 mL of 88% lactic acid has been added (to distilled water), this new spreadsheet predicts a mash pH of 5.45 versus Brun Water's prediction of 5.14. Most of this difference is due a difference in the contribution of the acid. In general, this new spreadsheet give results very similar to Kai's on-line calculator.
Utahbeerdude. This is fantastic information. I've partially read the papers (are these intended to be published in a journal?) and will read them in more detail shortly. Did you write these? If so - kudos. In particular, your point that "the slope of pH versus RA is too large" is exactly the point I was making. I asked Martin about this issue, he responded that my water alkalinity was probably variable - however - this can't possibly be the issue, because the alkalinity of my water would have had to have been well outside the annually measured range to give me the results I got. I used the new spreadsheet, and got a mash pH of 5.37 for the same recipe Brun water predicted 5.0; much closer to my measured pH of 5.45. I don't intend on using Brun water again. Attention to those of you using Brun water - there is more up to date and accurate data out there (looking at the papers I wished I had used Kaiser's water calc earlier - but I suspect the new model is even better for prediction.) Thank you, this is very helpful.
My understanding at this point is this: the slope of residual alkalinity adjustments versus pH is too high on Bru'n water; meaning that adjustments to pH seem more dramatic than they actually are. However, acid has more of an effect on mash pH than salts, therefore if you are using acid to adjust pH, you are more likely to be off - salt adjustments only are less likely to be off. Additionally, the density of the acid used varies with the concentration. This is not factored into Bru'n water. Finally, the % of lactic acid contained in acidulated malt used on the Brun water model is slightly lower than actual; therefore, using acidulated malt to adjust pH will lead to a more dramatic shift in pH than you might expect. All of these things have jived with my actual experience. I spent some time reviewing records versus pH prediction, both in Brun and the new mph sheet, and have found pH predictions are more accurate with the new sheet. No disrespect to Martin Brungard here - his sheet blew me away when I started using it. But, it is clear to me that the knowledge has already advanced on this subject (just in the last month.)
Glad the papers are of help. If any details are unclear, BM me. No plans to publish in a journal as I cannot image any journal where they would be appropriate. The papers are (perhaps obviously) aimed at the technically oriented homebrewer, but I hope the information contained within can be helpful to most any homebrewer who is serious about understanding how the grist and water ions affect mash pH. The spreadsheet calculations are also now part of Vikeman's brewing logsheet. I plan to next put some effort into understanding how ions impact flavor (beyond mash pH). Perhaps another paper will follow...
I'd love to understand final pH and impact on flavor. I suspect (again, based on experience) that it has more of an impact than most literature discusses (although Wild Brews sort of makes this point clear with regards to the correaltion between acidity and sourness.) I plan, in the near future, to begin measuring final pHs of my beers, and perhaps document any trends.
