ajdelange

Recipes 

The Primer represents the experiences of its author. Bru'n water represents the experiences of its author. Those two brew different styles of beer using different techniques and, doubtless, take pH measurements at different times. In either case you are comparing 2 models (and there are others - the EZ spreadsheet for example gives results more consistent with the Primer). Models are models and none is perfect. That is why good pH measurement is so important. Primers and spreadsheets are fine for rough planning but you really need the measurement to confirm. This is why you must be confident in your meter readings. You aren't the first guy to have chased pH because of a drifting meter.

If you took readings you did, checked with the buffers and found the cal was good then we have a real problem trying to explain an initial mash pH of 5.8.

If you haven't already done so I would suggest reading the pH Calibration sticky and making sure that you are following all the recommendations there especially the inter sample/buffer DI water rinses, fresh buffer and uniform temperature ones.

You asked about getting grains out of the electrode. This is important for a couple of reasons. Obviously the bulb will sense the pH of whatever is in contact with it. This should be 100% the new solution - not partially a piece of grain from a previous sample. The other reason is that the most common cause of poor performance from a pH meter is obstruction of the junction (you will see three things sticking out the bottom of the electrode: 1)the bulb 2) an RTD or thermistor 3) the junction.) A piece of grain or husk could easily cover the junction.

chilitom

Recipes 

It seems pretty clear that something is amiss with my measurements. That I accept. And thanks for the info about measurement & calibration -- I'll check the sticky.

Not to belabor the point (although it's getting a little belabored by now anyway) ... but quite independent of any model, many people seem to be using RO or distilled water now. Is the general experience:

- I have to add some acid to achieve the target pH, except when brewing dark beers with a significant amount of roasted malt

or

- I have to add alkalinity to achieve the target pH, except for very light beers

Seems like there would be one answer to this, regardless of who is brewing the beer.

Yooper

Recipes 

In my experience, using RO water and adding some salts, the first is true. I often need to add acid malt if I'm not using dark/roasted/crystal grains. Not much, often only 1%, but some.

I can't imagine ever needing to add alkalinity, unless using RO water and using roasted grains, like in a stout. For a stout, I use tap water but for all other beers I use RO water.

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ajdelange

Recipes 

I use RO water for almost everything and find that I need some acid in most cases - even for rather dark beers. I don't brew the ultra-uber-imperial-super stouts but I have never had to add alkali to a brew (though I do remember chasing pH as in the OP once). Note that when I do do stout I use tap water with alkalinity of about 70 and find pH a bit on the high side though I don't bother with acid in that case.