Hops in Whirlpool - HSA?
Sierra Nevada (among others) adds whole cone hops at flameout, or in the whirlpool itself. Kunze (2010 edition and Briggs, 2004) both mention milling cone hops directly into the copper, with Kunze mentioning adding milled hops just before the WP.
In addition, Kunze recommends cooling between the kettle and the WP to
80*C/176*F to increase the hop aroma.
HSA - it seems like pellets would contribute less oxidation to the hot wort because there is less air entrained in them than in whole cones (Sierra Nevada, e.g.) or milled hops (Kunze, Briggs).
Question: In the latter two cases are we not introducing significant oxygen to hot wort - something we all know we're supposed to avoid? Isn't this why the underback has lost favor?
I understand Sierra mashes under nitrogen. Obviously they take lipoxygenase and 2-transnomenal quite seriously. How do they deal with the entrained air in hop cones added at flameout or in the WP itself. [Their hop torpedo is a different technology entirely] How can Kunze (one of the primary porponents of HSA) suggest adding milled hop cones which also seems to add significant entrained oxygen to hot wort in the WP?
Any ideas on this? Am I missing something obvious?
Hidden Well Brewery
Kunze: Technology, Brewing and Malting, p. 371
Briggs: Brewing Science and Practice, p. 341
As I have heard they (Sierra Nevada) also store their hops under nitrogen, so I guess the theory is they don't introduce any oxygen with hop additions either. If you are going to go through the trouble to mash under nitrogen I guess go all the way !
At near-boiling temps, oxygen is almost completely insoluble. Unless you're going to follow Kunze's advice to lower the temperature between the kettle and whirlpool, I think the oxidative potential between whirlpool hops and boil hops is negligible.
I guess I was thinking about dry hops and oxidation!
A good graph of oxygen solubility:
Temp and Soluble Oxygen; nitrogen barrier
That is a very helpful graph. Thank you for sharing it. Makes sense about the hops being stored in nitrogen as well.
Do you have any idea how LONG it takes at a given temp to eliminate the oxygen? I see the same three general numbers (15, 30 and 60 minute boil) published in most of the primary brewing tomes - often all three in the same books, but with no test data or references to back any of it up (Kunze, Briggs, Lewis, Priest, Hardwick, Moll, DeClerck, Bamforth, Ockert, etc.).
BTW - Kunze recommends three different temps to lower the wort to prior to WP. It looks like he changed his views over the years and book editions but didn't catch all of the contradictory references. Take your pick - 80, 85 and 90*C! Briggs mentions reducing the wort to 192*F just prior to the WP (in the context of DMS) but again, gives no indication of why he chose that temp. Most temp references to SMM converting over to DMS are much lower than that - anywhere from 70-85*C depending on the source.