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Tetrahydropyridine

No change in size, 21:00, 21 December 2018
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* [https://www.morebeer.com/articles/malt_flavors "Flavors From Malt" by Scott Bickham on MoreBeer.com.]
* [https://beersensoryscience.wordpress.com/2011/06/02/corn/ "A pretty corny post" on the "Beer Sensory Science" blog (explains how 2AP could also be confused with DMS).]
 
===THP in Kettle Souring===
THP or THP-like flavors have been reported in the kettle souring process at a commercial breweries. This could be caused form using a heterofermentative species of ''Lactobacillus'' that is able to produce THP, but it has also been reported when an extended second boil was performed. Alex Wright reported that At Halo Brewery brewmaster Callum Hay was able to remove a THP-like flavor from their kettle sours by eliminating the boil time during the pasteurization step of kettle souring (the second boil) and displacing the trub at the bottom of the kettle. It was hypothesized that the boiling and perhaps the trub at the bottom of the kettle that built up after a 24 hour souring process was being heated by their direct fire system, causing Maillard reactions that resulted in pyradines. By scrapping the trub off of the bottom of the boil kettle, and replacing the second boil with a 75°C (167°F) 10 minute rest/whirlpool, they were able to remove this flavor <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/2381638895197644/?comment_id=2383092551718945&comment_tracking=%7B%22tn%22%3A%22R%22%7D Alex Wright. Milk The Funk Facebook group thread on THP in kettle sours. 11/24/2018.]</ref>. However, Alan Simons (and possibly others) contradict this by reporting no THP-like flavors when doing an extended second boil after kettle souring <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/2381638895197644/?comment_id=2383092551718945&reply_comment_id=2383152158379651&comment_tracking=%7B%22tn%22%3A%22R6%22%7D Alan Simons. Milk The Funk Facebook group thread on THP in kettle sours. 11/24/2018.]</ref>. Josh Kauffman reported that by switching from a 60 minute post-boil (after souring the wort with ''Lactobacillus'') to a 15-20 minute pasteurization rest at 180°F reduced the THP-like flavors in their kettle soured beer <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/2425689770792556/ Josh Kauffman. Milk The Funk Facebook group thread about THP in kettle sours. 12/18/2018.]</ref>.
==Production==
Since a low pH hinders the detection of THP, one detection used by wine makers is to rub some wine on one's palm and smelling for THP. A more reliable method is to dip an alkaline paper strip into the wine, and then smelling the strip to detect the aroma of THP <ref name="Grbin_1996" />.
 
===THP in Kettle Souring===
THP or THP-like flavors have been reported in the kettle souring process at a commercial breweries. This could be caused form using a heterofermentative species of ''Lactobacillus'' that is able to produce THP, but it has also been reported when an extended second boil was performed. Alex Wright reported that At Halo Brewery brewmaster Callum Hay was able to remove a THP-like flavor from their kettle sours by eliminating the boil time during the pasteurization step of kettle souring (the second boil) and displacing the trub at the bottom of the kettle. It was hypothesized that the boiling and perhaps the trub at the bottom of the kettle that built up after a 24 hour souring process was being heated by their direct fire system, causing Maillard reactions that resulted in pyradines. By scrapping the trub off of the bottom of the boil kettle, and replacing the second boil with a 75°C (167°F) 10 minute rest/whirlpool, they were able to remove this flavor <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/2381638895197644/?comment_id=2383092551718945&comment_tracking=%7B%22tn%22%3A%22R%22%7D Alex Wright. Milk The Funk Facebook group thread on THP in kettle sours. 11/24/2018.]</ref>. However, Alan Simons (and possibly others) contradict this by reporting no THP-like flavors when doing an extended second boil after kettle souring <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/2381638895197644/?comment_id=2383092551718945&reply_comment_id=2383152158379651&comment_tracking=%7B%22tn%22%3A%22R6%22%7D Alan Simons. Milk The Funk Facebook group thread on THP in kettle sours. 11/24/2018.]</ref>. Josh Kauffman reported that by switching from a 60 minute post-boil (after souring the wort with ''Lactobacillus'') to a 15-20 minute pasteurization rest at 180°F reduced the THP-like flavors in their kettle soured beer <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/2425689770792556/ Josh Kauffman. Milk The Funk Facebook group thread about THP in kettle sours. 12/18/2018.]</ref>.
==Off Flavor Kits==

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