Mash pH of 5.9+....whats the time frame for tannin extraction?

Say you have a mash where the pH is high (5.9/6.0 or above like the title says). How long does it take for the tannins to form, or extract? Are they fixable past a certain time?

The reason I am asking is I have seen some posts where people are doing short mashes, and some are even saying that conversion is done within 15-20 minutes. I assume they are using a fine grind on the grains.

If I am taking a pH reading at 10 or 15 minutes, and a large percentage of conversions have already occurred, then if I encounter a high pH problem, is it too late to fix with lactic acid?

I'm BIAB, btw.

 

It isn't tannin extraction that drives brewers to low mash pH though if you go over pH 6 I guess that could become a concern. And it isn't enzyme efficiency either. It is simply that the beer tastes better the lower the pH (without limit according to Kunze though I think most of us would be afraid to go below 5.2). So if you strike a mash and find out it's pH is 5.9 will you be able to save the beer if you can get the pH down to 5.4 withing X minutes? I really don't know but I would guess that it will be better if you do as opposed to doing nothing but not as good as it would have been had you hit 5.4 at strike.

 

Tannin extraction requires a certain pH AND a certain temperature. That's how brewers can get away with decoction mash, which is literally boiling a portion of the mash, grains and all, and adding back into the mash to raise temp. The recommended sparge temp limit is about 168 IIRC. The temp limit is recommended because the mash has been drained and the pH of the grain plus sparge water might rise above the recommended.

 

The theory is that it is the pH that prevents tannin extraction in the boil of a decoction. I think the phenols do get extracted in a decoction but since decoctions are done with lager beers (and wheat beers that have few husks) there is time, during lagering, for those phenols to complex and fall out.

 

I'm less inclined to attribute tannin extraction to pH and temperature. As AJ points out, decoctions have long been used in brewing and they generally don't experience that tannin issue. In my experience, its low wort gravity and the lack of sugars in the fluid in contact with the grain that invite tannin extraction. Oversparging to too low a runoff gravity is when my beers get into trouble. I'm doubting that a minor excursion into high wort pH during the mash is going to be terrible, but lowering that pH in the kettle is important for the subsequent beer flavor. I understand that a standard German brewing practice is to mash around 5.4 and reduce pH in the kettle to around 5.2 with an addition of soured wort.

 

If I have my mash pH correct (say 5.2-5.5) @ 10 minutes into the process, is there ever a reason to worry about kettle pH? Is there some ingredient addition, or some other process, that would drive the kettle pH into an unwanted zone while having a good mash pH?


FTR, I'm not having these problems, I'm just curious as to the chemistry and outcomes.

 

Quite by coincidence I was reading the late, lamented Dr. Kunze this morning and that is exactly what he says they do. I have said for years that if you get the mash pH right the rest of the process pH values track and that is more or less true (AFAIK) but I do think a little nudge in the direction of lower knockout wort pH is probably a good idea.

 

As I was opining while you were posting, I think the answer is 'no' barring something quite unusual. But I do think we might help things somewhat by a small additional acid addition.

 

How would late additions of roast malt change things up? A couple examples below:

1. I did an oatmeal stout where I held back the roast malt and cold steeped it. I then added the steeped wort @ 50 minutes into the boil. The 2-row, C120, Oatmeal, and Munich were mashed as normal. I aimed for a mash pH like a stout, 5.5, and wound up with 5.53. Was I correct in treating the mash like I brewing a stout even though the roasts were held off until very late?

2. What about if the roast malts were just held off until 45 minutes into the mash? I've seen Gordon Strong recommend this. Should I aim for the 5.5 stout pH @ 10 minutes into the mash, or should I try and aim for the 5.5 with the roasts added (aim for 5.5 @ 50 minutes into the mash)?

3. Am I overthinking this? (You can say yes, its cool).

 

You would not be able to rely on roast malt as a source of the protons required to get the base malt to the proper pH for best flavor from the base malt. At the same time the roast malts become a source of the acid that may perhaps be needed to get the wort down to its proper pH. OTOH its acidity may be too much and push the wort pH too low but I don't even know what too low is for a wort. Kunze seems to think the lower the better but doesn't specify a limit (that I've found).

As you reached a suitable mash pH of 5.5 I'd say yes.

I'd say aim for 5.5 at the beginning of the mash. That is when the base malts will release their flavors. Fifty minutes in the job should be done and you can start moving towards kettle pH.

No, don't think so.