Changes

Brewers have had positive and interesting results dry hopping sour and funky beer. Often fresh American or New Zealand varieties that compliment fruit flavors are chosen, however , other varieties have been used as well, including English and German hops. Just as in dry hopping normal beers, dry hopping sour/funky should be done after the beer has matured. Dry hopping for around 1-3 days before [[packaging]] the beer is adequate for extraction, depending on whether or not the beer is recirculated or agitated (agitation of the beer while on contact with the dry hops attains full extraction in 24 hours) <ref>[http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/34093/Wolfe_thesis.pdf?sequence=1 A Study of Factors Affecting the Extraction of Flavor When Dry Hopping Beer (master thesis). Peter Harold Wolfe. 2012.]</ref>. Hopping rates generally range from 0.5-1 ounces per 5 gallons of beer (1-2 pounds per bbl) to achieve hop-forward flavors, although lesser rates can be used to achieve a more subtle character (see the threads below) <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1693639013997639/?comment_id=1693660390662168&comment_tracking=%7B%22tn%22%3A%22R4%22%7D Nate Walter and Dan Pixley. Milk The Funk Facebook group. 05/21/2017.]</ref>.

Dry hopping can contribute to bitterness in beer through oxidized alpha acids and oxidized beta acids. Alpha acids will also dissolve into the beer, which are estimated as being 10% as bitter as iso-alpha acids. Dry hopping also has a linear impact on the pH of beer regardless of the starting IBU or pH: the pH rises by 0.14 per pound of hop pellets per barrel of beer in a beer that started with a pH of 4.2 (~0.5 ounces per gallon) <ref name="Maye_2016" /><ref name="Shellhammer, Vollmer and Sharp, CBC 2015"/>. This rise in pH might be less in more acidic beers that are dry hopped since pH is a logarithmic scale. Dry hopping can also reduce head retention in beers, although this is variety dependent (one study found that dry hopping with Eureka and Apollo hops increased head retention, while dry hopping with Bravo, Centennial, and Cascade decreased head retention). Extended dry hopping times (after 3 days) can also reduce head retention <ref name="Maye_EBC2017" />.