Help me understand this

[Raisoshi]

I was messing around with the EZ water tool, input some fairly soft water with low alcalinity data I got from the 5gal water carboy I buy at the store:

(9.66 Ca ppm) (4.89 Mg ppm) (5.57 Na ppm) (1.71 Cl ppm) (23.3 SO4 ppm) (37.92 HCO3 ppm)

Then I input the following stout recipe:

8.72gal Mash Water
19.8lbs Base Malt - 6-row
7.7lbs Base Malt - Other
3.26lbs Roasted Malt
1.1lbs Crystal Malt 53L


So... low alkalinity and roasted malts, I should be getting a pretty low mash pH, right? Guess not, as it turns out a 5.65pH. I try the following changes:

0 alkalinity... still 5.62pH
0 alkalinity and 9.77lbs Roasted Malts(3x original)... still 5.47
Only as I add some Gypsum or Calcium Chloride, and only at this extreme case of a ton of roasted malts and 0 alkalinity, does it get below 5.4.

So am I right to think it's pretty damn hard to get a mash pH that is too low? High carbonate water would only make it even more difficult. What am I missing?

 

[zwiller]

Your gut instinct is correct, something's wrong. Hopefully someone with experience with EZ water comments, as I am more familiar with BNW. A wild guess is don't have a roasted grain selected in the drop down (I used 2.0 years ago).

 

[ajdelange]

About as high as I can get making what I assume to be reasonable assumptions about the properties of the malts you are using is 5.48 but keep in mind that I am just guessing too. Who knows what you will actually get when you stick a pH meter into the real mash. Many of the existing spreadsheets have very primitive models of malt acidities based on color, empirical observation etc. I have a more sophisticated model but little real data for it. Take your pick.

 

[Raisoshi]

I tried BNW and achieved 5.3 pH. Granted this one was a bit more complicated(I like it better though), so more chances for me to make a mistake somewhere but... it's still not too low, as I initially thought it would be.

Guess I'm just going to trust it until I can get my hands on a precise pHmeter.

 

[ajdelange]

General observations on comments made here are that Bru'n tends to be low and EZ high. In this case if you take the average you get 5.475 which is very close to what I estimate.

 

[zwiller]

No time to run your data, but I plugged some quick numbers with similar bill (is this a porter?) into BNW with my water (90ppm alk) and get 5.2. I brewed a long time without water spreadsheets and I know dark beers with my water end up too low. Acrid and astringent. I can only surmise your water (which is great!) will make things worse for dark beers. Baking soda helped me dial it in and I suggest that to you but pickling lime does the trick if you got some. Depending on yeast, I prefer an elevated mash pH/wort pH for dark beers and aim 5.5-5.6 these days with english yeasts/ales. Chico produces less acid and you might be able to pull it off with 5.3 for an american style porter like SN. Semi related: http://forum.northernbrewer.com/viewtopic.php?f=1&t=117439