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Whenever I read or hear about decoction mashing, the issue of husk tannin extraction doesn't seem to come up and the impression that I get is that we don't need to worry about it. Why is it, though, that we don't need to worry about extracting tannins from husk when we're boiling a portion of the mash for up to 45 minutes, but we do need to worry about tannin extraction if we sparge above 172°F? I've gone through Noonan's New Brewing Lager Beer and this question isn't addressed. Any knowledge you have on this would be greatly appreciated!

Whenever I read or hear about decoction mashing, the issue of husk tannin extraction doesn't seem to come up and the impression that I get is that we don't need to worry about it. Why is it, though, that we don't need to worry about extracting tannins from husk when we're boiling a portion of the mash for up to 45 minutes, but we do need to worry about tannin extraction if we sparge above 172°F? I've gone through Noonan's New Brewing Lager Beer and this question isn't addressed. Any knowledge you have on this would be greatly appreciated!

That makes sense! Your response is a great reminder that low pH is an important factor in husk extraction during sparge--not just temperature. 

Whenever I read or hear about decoction mashing, the issue of husk tannin extraction doesn't seem to come up and the impression that I get is that we don't need to worry about it. Why is it, though, that we don't need to worry about extracting tannins from husk when we're boiling a portion of the mash for up to 45 minutes, but we do need to worry about tannin extraction if we sparge above 172°F? I've gone through Noonan's New Brewing Lager Beer and this question isn't addressed. Any knowledge you have on this would be greatly appreciated!

Whenever I read or hear about decoction mashing, the issue of husk tannin extraction doesn't seem to come up and the impression that I get is that we don't need to worry about it. Why is it, though, that we don't need to worry about extracting tannins from husk when we're boiling a portion of the mash for up to 45 minutes, but we do need to worry about tannin extraction if we sparge above 172°F? I've gone through Noonan's New Brewing Lager Beer and this question isn't addressed. Any knowledge you have on this would be greatly appreciated!

Hi Nassim,
The book New Brewing Lager Beer does mention astringency extraction on page 136. But Noonan only discusses this issue in a small section: "probably because the density and pH of the decoction prevents phenols from being leached out of the husks." Therefore, I believe the reason is for sure low pH due to concentrated wort compared to the wort during boiling. 

Whenever I read or hear about decoction mashing, the issue of husk tannin extraction doesn't seem to come up and the impression that I get is that we don't need to worry about it. Why is it, though, that we don't need to worry about extracting tannins from husk when we're boiling a portion of the mash for up to 45 minutes, but we do need to worry about tannin extraction if we sparge above 172°F? I've gone through Noonan's New Brewing Lager Beer and this question isn't addressed. Any knowledge you have on this would be greatly appreciated!

Hi Nassim,
The book New Brewing Lager Beer does mention astringency extraction on page 136. But Noonan only discusses this issue in a small section: "probably because the density and pH of the decoction prevents phenols from being leached out of the husks." Therefore, I believe the reason is for sure low pH due to concentrated wort compared to the wort during boiling. 

Whenever I read or hear about decoction mashing, the issue of husk tannin extraction doesn't seem to come up and the impression that I get is that we don't need to worry about it. Why is it, though, that we don't need to worry about extracting tannins from husk when we're boiling a portion of the mash for up to 45 minutes, but we do need to worry about tannin extraction if we sparge above 172°F? I've gone through Noonan's New Brewing Lager Beer and this question isn't addressed. Any knowledge you have on this would be greatly appreciated!

Whenever I read or hear about decoction mashing, the issue of husk tannin extraction doesn't seem to come up and the impression that I get is that we don't need to worry about it. Why is it, though, that we don't need to worry about extracting tannins from husk when we're boiling a portion of the mash for up to 45 minutes, but we do need to worry about tannin extraction if we sparge above 172°F? I've gone through Noonan's New Brewing Lager Beer and this question isn't addressed. Any knowledge you have on this would be greatly appreciated!

Probably a good idea to read through this older article; https://www.mbaa.com/publications/tq/tqPastIssues/1967/Documents/4_98.pdf

Cheers, Keith

Whenever I read or hear about decoction mashing, the issue of husk tannin extraction doesn't seem to come up and the impression that I get is that we don't need to worry about it. Why is it, though, that we don't need to worry about extracting tannins from husk when we're boiling a portion of the mash for up to 45 minutes, but we do need to worry about tannin extraction if we sparge above 172°F? I've gone through Noonan's New Brewing Lager Beer and this question isn't addressed. Any knowledge you have on this would be greatly appreciated!

I also must question Noonan's interpretation.  M. Jurkova et al. (J Inst Brewing, 2012) found that decoction mashes actually did extract more polyphenols than infusion mashes.  And through my own research I have found that total polyphenol concentration in fact decreases over the course of the lauter (though the ratio of polyphenols to extract increases.)  Not that I doubt the findings of Schuster and Raab regarding "herbstoffe", cited in Mr. Armstrong's reference. The only myth I'm here to bust is the notion that the role of malt-derived polyphenols is simple.  A review of the literature shows the many different types of polyphenols in wort, and their various tendencies to form trub/break, impart bitter and stale flavors, lead to chill haze, protect the beer from oxidation, and contribute to mouth-feel.  I think Mr. Heasley's answer is credible, but Mr. Sultan's question remains a good one.

Probably a good idea to read through this older article; https://www.mbaa.com/publications/tq/tqPastIssues/1967/Documents/4_98.pdf

Cheers, Keith

Whenever I read or hear about decoction mashing, the issue of husk tannin extraction doesn't seem to come up and the impression that I get is that we don't need to worry about it. Why is it, though, that we don't need to worry about extracting tannins from husk when we're boiling a portion of the mash for up to 45 minutes, but we do need to worry about tannin extraction if we sparge above 172°F? I've gone through Noonan's New Brewing Lager Beer and this question isn't addressed. Any knowledge you have on this would be greatly appreciated!