Added gypsum to a partial mash porter recipe, and now wondering why. Mistake or no?

[marshall_tucker]

So before you slap me on the wrist, i've already scolded myself for this. I wasn't able to check pH levels in the mash because i either ran out of or misplaced my test strips, so yes, i was flying blind and ran the risk of doing more harm than good.

so anyway, the mash: 1.4 quarts water per pound grain, total of 6.65 quarts and 4.75 lbs. single step mash around 156 F, 60 min.
2 lbs Rahr 2-row
0.5 lb chocolate malt
1 lb english med crystal
1.25 lbs flaked oats

the water i've been using usually averages around this:
Alk as CaCO3 150 ppm
Ca 66 ppm
Cl 16 ppm
Mg 10 ppm
Na 8.5 ppm
SO4 43 ppm
pH 6.3-8.1 (that doesn't narrow it down too well...)

in short, i was RDWHAHB'ing and got my wires crossed. i forgot that gypsum actually LOWERS pH, not raises. at the time, i haphazardly thought to myself i'd throw in 1/2 teaspoon to the mash to counteract the dark malts acidity. duh...:smack:

worse problems can happen, i know. probably not the end of the world, but how detrimental do you think this mental hiccup could end up being?

 

[Gavin C]

Right tools for the job

1: Lost test strips. Good, don't find them. Not useful if the experts are to be listed to. (I tend to listen to them). Use a good meter, one with a track record of stable readings. There are a few recommended ones in the brew-science thread on the topic. Or use no meter and fly blind

2: Mineral additions for adjusting pH is not a very good idea as the amounts needed to bring the desired results will massively alter the flavor of the beer.
This is the seasoning of the brewing water.

3: Mash pH can be easily adjusted with tiny additions of acid or acidulated malt.

*Adding alkali (not with gypsum) if needed but if you get an acurate water report, good, accurate, well calibrated pH meter and use powerful predictive tools to calculate mash additions (of acid) you will never need alkali with that water. You've got plenty.

In short, if you want to tackle water chemistry and mash pH I would advise rethinking your approach.

 

[Yooper]

Luckily, 2.5 grams of gypsum shouldn't add a ton of sulfate.

Think of gypsum as "salt" for hoppy beers. It enhances the perception of dryness, and brings out the bitterness of hoppy beers. You don't want it in a porter at all, but at least 2.5 grams is a pretty small amount. Unfortunately, you already have quite a bit of sulfate in that water so you've about doubled it.

Next time, use baking soda to raise the pH of a mash (but it's only VERY rarely needed and shouldn't be needed at all with that water), and lactic or phosphoric acid to lower the pH (which you generally do need).

 

[marshall_tucker]

yeah, i did some reading after posting this thread and came to the same conclusion that there really was no need to be adding much of any salts to this one. duly noted.

flavor-wise, i'm wondering if some of the gypsum got carried away though with the removal of the grain...we shall see. let's just say i have a poor man's approach to mashing grain and probably don't get as complete a sparge as others do.

one of my major concerns was possibly acidifying the mash too much, but if i crunched the numbers correctly with the brewer's friend worksheet, it was probably a minimal drop. in the process, i learned an interesting tidbit about enzyme activity. see koopa's post about 1/3 down.
http://www.beeradvocate.com/community/threads/mash-ph.63267/