Mash pH was off, although I followed Bru'n water.

[fat_astronaut]

I followed Bru'n water, and I used RO water that I had tested to find that the pH was 5.5. When I tested my mash pH, (with pH strips), my pH read about 4.6. I stuck the strip in the mash, which was at 154*F, (would this affect my reading, by dropping it?).

Here is my brewing additions sheet : http://www.docdroid.net/hl2s/pumpkin2.pdf.html

I added a bit of straight boiling 5.5 water to the mash, (about 1 litre), to bring the temp up at mash in. I also added about 3 lbs of baked pumpkin, that I didn't account for in my calculations.

Would using 5.2 buffer be worthwhile next time? I haven't brewed in a couple years, and this is my first time adjusting the water myself as well. Any help would be greatly appreciated!

 

[ajdelange]

I followed Bru'n water, and I used RO water that I had tested to find that the pH was 5.5.

This should have been your first clue that something was wrong. If your RO water is DI, i.e. completely pure and the alarmists are right (PaCO2 = 0.0004 atm) then the pH of the water would be around 5.5. But if your RO system passes as much as 1 mg/L bicarbonate you would expect water pH to be about a point higher. Practically speaking, RO water usually measures in the mid 6's in the lab. What you saw demonstrates the well known fact that pH strips are pretty useless in the brewing application.

When I tested my mash pH, (with pH strips), my pH read about 4.6. I stuck the strip in the mash, which was at 154*F, (would this affect my reading, by dropping it?).

Under the best of circumstances strips are notorious for reading on average about 0.3 pH low in wort. The best of circumstances includes cooling to room temperature. I have no what mash temps might do to them but I'll bet it doesn't improve their accuracy. Also note that when you see pH values given here and in most of the literature it is referring to room temperature.

Note also that the spreadsheets and calculators are often off by quite a bit (though they are often pretty close too) in their pH predictions. They shouldn't be thought of as giving a prediction accurate to more than ±0.1 - ±0.15 pH. They simply do not know enough about the malts you are using.

If you are going to pursue this and if you want to be able to use the spreadsheets effectively you will need a pH meter. They are now available at accessible prices.

Would using 5.2 buffer be worthwhile next time?

No. It is pretty useless too. Put it on the shelf with your pH strips.

 

[mabrungard]

Paper pH strips are worthless in brewing application. There is no way that a pale mash with little added calcium and no added acid would produce a pH anywhere near 4.6. The 5.5 pH is much closer to the truth and that is still too high for most pale beers. You probably still needed to add a bit of acid to that mash to help drop the pH into a desirable range.

If you want to measure pH, you should employ a calibrated pH meter and measure the sample at room temperature. That way, the number of errors is reduced.