Gypsum

I've been pondering the addition of gypsum in the IPA recipe.  What is gypsum and why is it an important ingredient in this IPA?

Gypsum is also known as Calcium Sulfate (CaSO4), a common brewing "salt".  It is a mineral that is quarried, and apparently was commonly mined in the districts around of Paris - hence the term "plaster of paris".  Gypsum is deposited from lake and sea water, as well as from hot springs and volcanic vapors - a deep earth mineral.

Who knew the uses of gypsum?  It spans the gamut of foods, water treatment, soil amendment, and binder for things like cement and clay.  And of course, gypsum is a key addition to gypsum board, or more commonly dry wall. In beer making, it is typically added to the mashing or boiling process.  Gypsum cripes!!

Charlie Papazian has a good write-up in his book.  In summary, the calcium (Ca) aids in the clarification of the wort and also helps to remove some of the tannins found in the husks of the grains.  Apparently if these are not removed, the beer can be hazy and well as have an "off" flavor.

The sulfates (SO4) add a dry, crispness to the beer.  Probably since this is an IPA, and that they tend to be drier, gypsum is added.  Papazian warns that over mineralization can really ruin a beer.  The type of brewing that I'm doing right now, where I'm leveraging malt extracts, I probably don't have to worry about adding minerals as it's probably already done in the malting process.  However since I'm doing partial grain steeping, some consideration must be for the tannin proteins that can be imparted.

I'll continue to follow recipes and add what they call for.  Here in Portland, we are lucky to have high quality city water from Sebago Lake.  It is a well-balanced water, neither too hard nor too soft.

On Wednesday night, I transferred the beer from my primary fermenter (a.k.a. my white bucket) to the secondary fermenter the carboy.  The foam, or kraussen, on the top was thick and viscous, while the brew itself had a heavy bread and hop aroma.  The hop sediment was quite significant as well.  It continues to ferment away in the carboy, and will probably do so for another week or so.

I also took a hydrometer reading, registering 1.022 gravity.  The initial gravity prior to "pitching the yeast" was 1.042.   Final gravity is supposed to be 1.014 - 1.018.  I need to learn more about gravity readings with a hydrometer, and what they specifically mean.  Perhaps my next post.

Stay tuned.  Bottling in a week or so!  The timing is good, since I'm down to my last two 22 oz. Bad Ass Mo Fo's (which I'm probably giving away to friends).  My last friends to try the BA Mo Fo had RAVE reviews!!