Gypsum, for those who are not in the know, is CaSO4 – calcium sulfate (we can thank dear Lavoisier for his nice nomenclature). It’s in your water, to varying degrees, depending on where you live. Locations with ‘hard water’ typically have much higher concentrations of it that Sydney, which has quite soft water.
Why the interest in the chemical composition? Well, it all starts with a beer called pacific ale. Or more specifically, various attempts to replicate it. From dry hopping, to last minute of the boil and rapid chilling, to proposing various bits of complex machinery, no one that I know has yet managed to replicate the delicious Galaxy (passionfruit) hop aroma of Pacific ale. So how do they do it?
Matt had the suggestion that it could actually be the water. Or more specifically, the lack of Gypsum in the water. Needless to say, I was eager to test this theory, to make Sydney water Harden the fuck up. Of course, I didn’t want to do this by any half measure, so I decided to go for an IPA – the HTFU Soft Water (St)ella galaxy.
232 g castor sugar
27g Ella 60mins
25g Galaxy 15mins
35g Galazy flame out
40g of CaS04
The brew was a nice quick one, and I went with some (out of date) Vermont yeast, that I had created a starter of. The final CaSO4 concentration was probably about 400ppm, so it might have been a little bit of overkill. No guts no glory, right?
Hopefully it’ll do the job, if not, it’ll be another bitter, delicious IPA (or it’ll get infected by all the sours I’ve been brewing)…