I live in the Bear Gulch Water district (on the SF Peninsula), but the report I get from the supplier does not have enough information to tweak my water recipe. So this month I had my water tested by Ward Labs.
Most of the San Francisco Peninsula from Menlo Park up to the City gets their water from the SF Municpal Water District, which gets it from a man-made resevoir in the Sierra Mountain Range called Hetch Hetchy
. If you live on the San Francisco Peninsula, it is likely that your water is exactly the same as mine, so you might find this data useful.
In fact I took four samples using different methods, and had all of them tested. The methods were:
1. Sample A: Filtered Tapwater
. I broke in a new activated carbon filter, then sampled some water passed through it.
2. Sample B: Unfiltered Tapwater
. I sampled some straight tapwater.
3. Sample C: Tapwater plus campden tablet
. I tapped 10 gallons, smashed in half a campden tablet, and waited 30 minutes, then sampled.
4. Sample D: Tapwater plus campden tablet, passed through brewing system
. I passed the 10 gallons of campden-treated water through my brewing system (without adding any heat or other ingredients), then took a sample from my fermenter.
The results of having these samples tested by Ward Labs are here
. I also included a record of the report from my water supplier, the California Water Service Company.
I think this water is pretty good. I've never tasted tap water as good as mine. And it seems pretty flexible when it comes to brewing. I just got a pH meter, and this weekend I made a Schwarzbier and measured the pH 15 minutes into the mash, it came out 5.4. I don't have my recipe handy but I'll document all that and post it later.
If anyone can think of other information I can provide about Bear Gulch water, please let me know!