Does a malts DI water pH change over time?

Has anyone on here measured the DI water pH of two samples of the same malt, from the same sack, say 6 months apart? I'm curious if the pH could change over that time. I can't think of any reason this wouldn happen other than the fact that there is some moisture in the malt and there are lacto bugs on the malt. I guess I'm curious because I just took the DI pH of a sample of Weyermann pils (100 grams in 300ml water) and it was lower than I'd expected, at 5.63. The DI pH of pils in EZ Water is 5.75, so there's obviously a big difference. I'm not sure what water to grist ratio was used, though (or if there's a ratio that is standardized on).

EDIT: I'd calibrated the meter earlier today, so it probably hadn't drifted too much.

I'm not sure about variation over time with the same sack of malt but there is certainly variation between maltsters. EZ got 5.75 somewhere. You measured 5.63 and on a batch I measured some time ago I got 5.67. I also wonder about batch to batch from the same maltster. And then the DI pH isn't the whole story. There is the alkalinity/acidity of the malt. How much does that vary from maltster to maltster? This is why it is important to understand that a computational model is no more than that and that while the data it provides can be used for planning purposes it cannot be relied upon to provide pH predictions which can be considered more than estimates.

The differences you observed can easily be explained by differences in hydration, temperature and measurement error of the meter. Also, if you are using home DI water, there can be differences in the quality of water exiting the unit depending on how depleted the DI resin is.

adamreef said:

The differences you observed can easily be explained by differences in hydration, temperature and measurement error of the meter. Also, if you are using home DI water, there can be differences in the quality of water exiting the unit depending on how depleted the DI resin is.

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The probe probably could be replaced, but the meter is rated at +/-.02 error. Also, the water was actually just distilled water, but I figured that's close enough for this purpose. I wouldn't think it'd make .12 pH difference, but I could be wrong.

The differences you observed can easily be explained by differences in hydration, temperature and measurement error of the meter. Also, if you are using home DI water, there can be differences in the quality of water exiting the unit depending on how depleted the DI resin is.