When is the appropriate time to make mash pH adjustments?

I'm just getting into brewing water adjustments and I appreciate all the help in this sub-forum.

My last mash came in at 4.9 but I didn't know when was the appropriate time to make an addition. Do I do it as soon as I take that first pH reading at mash-in? And if so, do I just add my measured Sodium Bicarbonate directly to the mash tun and stir it in? Lastly (for now), if I need to acidify the mash can I add Acid Malt directly to the mash tun after mash-in of everything else?

Thanks to all who take a second to look in here! I am lost without the expertise of the people on this forum.

See the discussion at https://www.homebrewtalk.com/f128/changing-my-mash-water-saved-my-beer-323473/

The general drift there is that you must wait 15 - 20 minutes for the pH to stabilize before making an adjustment. By this time it is really too late to make one, however, so a better idea is to mash a small amount of the grist you plan to use with the water you plan to use and check its pH after 15 - 20 minutes. If that is too high then add some acid (1% sauermalz per 0.1 pH drop desired is the easiest to compute certainly) or if too low then add small amounts of alkali until the desired pH is reached and then scale that amount for the full mash.

If you haven't done a test mash then go ahead and do the acid/alkali adjustment anyway. The beer will not be as good as it would be if proper pH were established immediately but it still can be very good. Next time you brew this beer you will have a better idea what to do.

Yes, you can make corrective additions directly to the mash.

I have to agree with AJ, but using a program like Bru'n Water can at least get you prepared for what additions are likely. I do think you should take care of mash pH ASAP. The test mash approach seems quite reasonable. If you're not into that approach, use Bru'n Water to get you close.

I tested this a bit today. I mashed it, stirred very very well, and checked the temperature. In 5 minutes I took my sample and cooled it. It read 5.45 at room temperature. In 15 minutes, I took another sample and got 5.39. In 30 minutes, it was still 5.39. Very close, but not exactly the same.

It takes me about 5 minutes to cool my small sample in an ice/water bath.

mabrungard said:

I have to agree with AJ, but using a program like Bru'n Water can at least get you prepared for what additions are likely. I do think you should take care of mash pH ASAP. The test mash approach seems quite reasonable. If you're not into that approach, use Bru'n Water to get you close.

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Yeah...I've tried using your program. I really admire the time and energy you put into it but it always ends up calculating a much higher pH than I end up with. It's great for calc'ing mineral content but hasn't worked so great for me with figuring pH. I'm sure I'm doing something wrong (e.g., it always says "unbalanced" for total anions on the "input water report" page) but I don't have the technical knowledge to figure out what it is.

The computer age adage: Garbage In = Garbage Out holds true. Until you input the water quality of your starting water correctly, there is no way that you'll get an answer that's worth a hoot.

klnosaj said:

but it always ends up calculating a much higher pH than I end up with.

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That makes me suspect that you are measuring pH with strips rather than a properly calibrated meter.

mabrungard said:

The computer age adage: Garbage In = Garbage Out holds true. Until you input the water quality of your starting water correctly, there is no way that you'll get an answer that's worth a hoot.

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I don't really know what that means. I called my water provider and had a nice chat with one of the engineers there. I entered the data as he provided them to me.

ajdelange said:

That makes me suspect that you are measuring pH with strips rather than a properly calibrated meter.

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No, no strips here. I use a Milwaukee pH 600 from Amazon. It's calibrated using 4.0 and 7.01 solution.

klnosaj said:

No, no strips here. I use a Milwaukee pH 600 from Amazon. It's calibrated using 4.0 and 7.01 solution.

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How'd you do that? I looked up the pH 600. It only supports calibrating at one point (probably 7.01).

i have been seeing about .2 lower than what ezwatercalculator predicts, with biab full volume mashing.

klnosaj said:

I don't really know what that means. I called my water provider and had a nice chat with one of the engineers there. I entered the data as he provided them to me.

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The data provided by the water authority will result in an imbalanced report unless
1. All the parameters are measured on the same sample on the same day
2. All the lab's measurements are perfect.

Neither of these ever pertains so there will always be an imbalance. One looks at the amount of the imbalance in judging the quality of a water report. In terms of ability to predict mash pH the water parameter of greatest significance is alkalinity with calcium a distant second and magnesium coming in pretty far behind calcium. Since a fairly alkaline water (alkalinity of 150) has a buffering capacity of about 1.7 mEq/L-pH and most malts 25 - 40 mEq/pH-kg which, assuming 1 qt/lb (2 L/kg) would be 12.5 - 20 mEq/L-pH it is clear that even the water alkalinity has a small effect compared to the buffering capacity of the malt. Thus it is malt buffering and malt acid content which are mostly responsible for determining mash pH and it is accurate data on the actual malts you are using that is required. Same deal with them. If you don't have good values (and they are hard to get) you will get poor pH prediction. Of course having poor water data doesn't help the situation at all but assuming the lab guy gave you fairly good alkalinity and hardness numbers the modest errors in those should not be significant contributors.

All that aside, you really can't expect much (other than that it should be better than a reading made with strips) of a pH reading made with a meter that uses single point calibration unless the pH being read is quite close to the buffer pH. Precision of 0.1 doesn't help either. In my experience Bru'n water tends to predict to the low side (though I think the model has been recently improved) which is why I asked whether you were using strips as they also tend to read low and could explain why Bru'n water's predictions were higher than your readings. But an error of 0.2 could easily be explained by 0.1 precision and a single point calibration i.e. assuming Bru'n water was spot on (which it can be or very close anyway) your meter could easily read 0.2 higher.

I see. I thought I had a good tool in my pH meter and I was proud of myself for tracking down water quality data requiring a good amount of phone work on my part. As far as the Milwaukee 600 model goes, I can say that after calibrating with 7.01 it reads the 4.0 solution as 4.0. In any event, this is all rather frustrating. I thought I was breaching new horizons with my brewing but apparently I'm still stuck in the dark with regards to manipulating brewing water. Thanks for all the help, though. It is genuinely appreciated.

klnosaj said:

As far as the Milwaukee 600 model goes, I can say that after calibrating with 7.01 it reads the 4.0 solution as 4.0.

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Well that's a good thing, of course. But does a indicated display of 4.0 mean 4.0 or 3.91 or 4.09? You just can't tell at that level of precision.

klnosaj said:

In any event, this is all rather frustrating. I thought I was breaching new horizons with my brewing but apparently I'm still stuck in the dark with regards to manipulating brewing water.

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Please don't get discouraged. This is an intricate subject. There are lots of places to stumble and lots of things to get hung up on but having an interest and trying to figure it out plus some experience, which can only be gained over time, will, eventually, result in appreciably better beer. It is worth the effort.

ajdelange said:

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Please don't get discouraged. This is an intricate subject. There are lots of places to stumble and lots of things to get hung up on but having an interest and trying to figure it out plus some experience, which can only be gained over time, will, eventually, result in appreciably better beer. It is worth the effort.

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