Beer again, but one on the warmer side...

Beer again, and this time my son-in-law paired his Dogfish Head 60 Minute IPA* with a quinoa-and-bean-based veggie burger. Very good beer, very good burger, and very good pairing!

Here's why:

First about the veggie burger: overall the burger had a warm/hot flavor profile, suggesting that together its ingredients activated the warm and hot receptors TRPV3 and TRPV1. At the same time, there was a first impression of a vegetal quality, perhaps grassiness, that meant that the beer lost nothing of its complexity when tasted with the burger. 

Now about the beer:

1. The beer is a light amber rather than the pale yellow of the Lord Hobo beer I described in my previous post, and it's even slightly more brown than you would expect to find in the usual IPA's. This means that it has "brown" chemicals that activate the warm and hot receptors.

2. While it has "piney & citrus notes" according to the description on the Dogfish Head website, which would be a sign that cool/cold receptors were activated (think of walking through a pine woods on a hot day!), the citrus side comes across to me as orangey rather than lemony, again a trait associated with the warm receptor activation. One reason may  may be that the "brown" nature of the beer shifts the balance away from "lemon" towards "orange."

3. Hops were added continuously to this beer during the 60 minute boil, hence the beer's name. With this addition throughout the boil, you get much higher levels of linalool in the final beer than you would if you only added hops at the beginning of the boil.** Interestingly, if you add hops after the boil (a process called dry hopping), you would not get any more linalool and probably even less. Linalool, in context with the other compounds, also contributes to the "orange" perception. 

4. Geraniol in the hops is transformed into β-citronellol, first during the boil, and thereafter by yeast.*** β-citronellol, found in oranges, also activates the hot receptor.**** Different varieties of hops have different proportions of geraniol, so how much of this compound is present in a beer would be of interest, in that it shifts the temperature activity from the cool/cold contributed by CO2 and by eudesmol, (the latter is a water soluble compound in hops that activates TRPA1, the cold receptor), to the warmer, more orangey side.   

5. Concentrations of β-damascenone, which has a damask-rose aroma, increase over time when the hops are added at the beginning of the boil, so may be expected to increase even more when the hops are added continuously during the boil.** This compound also activates the warm/hot receptors.

6. All that hopping extracts large amounts of eudesmol, a compound that activates the cold receptor TRPA1, which together with CO2, gives the beer its pungency.*****  

All of this brings together the reason I used the word complexity to describe the experience of this beer with this burger. As you first sip the beer, the quick-onset cool/cold receptors respond, and the pungency caused by activation of the cold receptor TRPA1 zings in. Then activation of the warm/hot receptors dominates, and the beer's orangey quality comes into focus. Then a bite of the burger, and the cycle repeats itself, first a quick cool and grassy, then warm/hot. The sweet carbs and the salt in the burger, meanwhile, cut enough of the bitterness in the beer to allow the aromas to sing. 

Delicious complexity, indeed!

* https://www.dogfish.com/brewery/beer/60-minute-ipa -- if you visit the site, be sure to see CEO Sam Calagione's short video about the beer 

** Toru Kishimoto,*, Akira Wanikawa,Noboru Kagami, and, and Katsuyuki Kawatsura. Analysis of Hop-Derived Terpenoids in Beer and Evaluation of Their Behavior Using the Stir Bar−Sorptive Extraction Method with GC-MS. Journal of Agricultural and Food Chemistry 2005 53 (12), 4701-4707. DOI: 10.1021/jf050072f.  
=> Note: the hop used in the experiments looking at compound concentrations over time was Hersbrucker, which by these authors' analysis had a high linalool to geraniol ratio.

*** Takoi K, Itoga Y, Koie K, Kosugi T, Shimase M, Katayama Y, et al. The contribution of geraniol metabolism to the citrus flavour of beer: Synergy of geraniol and β-citronellol under coexistence with excess linalool. Journal of the Institute of Brewing. 2010;116(3):251-60.

**** Ohkawara S, Tanaka-Kagawa T, Furukawa Y, Nishimura T, Jinno H (2010) Activation of the human transient receptor potential vanilloid subtype 1 by essential oils. Biol Pharm Bull 33:1434–1437.

***** Kazuaki Ohara, Takafumi Fukuda, Hiroyuki Okada, Sayoko Kitao, Yuko Ishida, Kyoko Kato, Chika Takahashi, Mikio Katayama, Kunitoshi Uchida, and Makoto Tominaga. Identification of Significant Amino Acids in Multiple Transmembrane Domains of Human Transient Receptor Potential Ankyrin 1 (TRPA1) for Activation by Eudesmol, an Oxygenized Sesquiterpene in Hop Essential Oil. J. Biol. Chem. 2015 290: 3161-. doi:10.1074/jbc.M114.600932.