Wednesday, August 23, 2017

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!

* -- 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.

Wednesday, August 16, 2017

My first sip of beer...

In honor of my talk about beer next month, I had my first sip of beer ever...and was pleasantly surprised! The stink of the stale beer of my youth, coupled with the fact that I can't tolerate alcohol, limited my desire to taste beer in the past, but for the sake of science, I decided to take a sip. 

It was a local beer from Lord Hobo, Woburn, Massachusetts, pale and cloudy, with very little head, a Session IPA, a style that was originally brewed in England in World War I for workers in armament factories. The requirement was (so I was told) that the brew should have less than 5% alcohol, to prevent drunkenness — this version clocked in at 4.5%.
This picture, from the Lord Hobo Brewing Company website, shows exactly what the beer looked like.
My son-in-law declared it "hoppy." What I sensed was a grapefruity bitterness, with a little tickle and sourness from the carbonation, and bitterness with a slight prickle lingering at the finish: a "clean" fresh impression overall. Nothing like anything I had tasted before, though on thinking about it, it was a bit like the Pompelmo (grapefruit) Fanta from Italy that my father loved (now discontinued, btw). 

For dinner, my son-in-law had a mildly spicy and salty, definitely umami meatloaf, with a rich barbecue sauce. He said that the beer mellowed out with this dish, so that it was less sharp, bitter, and flavorful, but still refreshing, and palate-cleansing. Later, well after he had finished the meal, when he drank the last sips of the beer, he said the original qualities of the beer returned.

Here's what I think is happening at the level of the taste buds, namely that the beer activated the cool/receptors (it was refreshing!) and my son-in-law's meatloaf activated the warm/hot receptors so the beer's qualities were muted. 

More about how this all works in another post. This beer thing really has me enthralled!

=>> Don't worry, am not forgetting tea — am also busy creating an extended course about pairing in general and pairing with tea in particular! Stay tuned!

And meanwhile, take a look at my book "Three Basic Teas & How to Enjoy Them" by Virginia Utermohlen Lovelace. You can find it on Amazon!

Friday, August 11, 2017

Port wine and tea

To continue my exploration of tea through library searches, came across a paper on the flavor chemicals in port wine... (don't ask how this paper came up when I searched for wonders about search algorithms sometimes!..not that I'm complaining: this paper on port wine was fascinating.*)

Although I don't drink alcohol for genetic/metabolic reasons (I can't detoxify alcohol's poisonous metabolite, actealdehyde) I have been fond of the flavor of certain alcoholic beverages, including port. Now I know why.

A glass of port, photo by Jon Sullivan that was a featured picture on Wikimedia Commons (Featured pictures) and was considered one of the finest images. 
A key step in the making of port is the addition of a wine-derived spirit called "aguardente" (burning water) obtained by distillation. This distillate increases the alcohol content of the port, but also contributes a number of volatile compounds to port's flavor.

Among these compounds are ones that make green tea so refreshing by activating the cool receptor TRPM8: 
- linalool, found in all teas, but dominating green tea, with its fresh flowery/citrus aroma;
- geraniol, found in geraniums (as its name implies) and in roses as well as all teas, which contributes a peach-like nuance; and  
- (Z)-3-hexen-1-ol, which contributes a grassy note to green tea, and in addition a slight pungency due to activation of TRPA1.

A couple of other flowery compounds in aguardente are more characteristic of oolongs and black teas, including: 
- beta-damascenone, the name of which derives from Damask roses, which has a more musty quality than many of the other rose-related scents in tea, probably from its ability to activate the warm (TRPV3) and hot (TRPV1) receptors; and
- benzaldehyde, which contributes a sweet, nutty, cherry/almond note to oolongs in particular (also an activator of TRPV3). 

So the next time you have a glass of port, look for the flavors of your favorite tea, and vice versa!


Just a reminder: if you would like a compilation of knowledge about tea flavors, their sources and their effects on nose, mouth, and brain, you can find it in my book: "Three Basic Teas & How to Enjoy Them," by Virginia Utermohlen Lovelace, available on Amazon.

Rogerson, F.S.S. and De Freitas, V.A.P. (2002), Fortification Spirit, a Contributor to the Aroma Complexity of Port. Journal of Food Science, 67: 1564–1569. doi:10.1111/j.1365-2621.2002.tb10323.x

Wednesday, August 9, 2017

What's to love about garlic?

So many things! But one in particular is fascinating: garlic's ability to block the aversiveness of high levels of salt.

In my mother's pre-culinary days, she used to make a salad dressing with vinegar, a generous dose of salt, and very little oil because she felt that oil was fattening (those were the days when good olive oil was hard to come by, and we couldn't have afforded it anyway). I used to hate salads—the sourness of the vinegar made me shudder, and the bitterness of the greens was intolerable. 

Then somewhere when I was around 11 or 12 she discovered the trick of rubbing the salad bowl with garlic (she still hesitated actually including the garlic in the dressing itself). Suddenly salads were much more palatable for me.

Cross-section of garlic bulb, from Darnok at

Garlic contains a compound, allyl isothiocyanate, that gives it the garlicky flavor, This compound (henceforth "AITC") also activates the cold/pain receptor, TRPA1, in the mouth, hence garlic's pungency. 

In experiments with mice, Oka and colleagues used AITC to dissect how high concentrations of salt (NaCl) become aversive.* 

It turns out that, while low concentrations of salt inhibit bitter-sensing taste bud cells, high concentrations of salt activate these cells and also activate sour-sensing cells. That's why high salt can bring out the bitterness of your salad greens and the sourness of the vinegar in your dressing. These activations can be inhibited by AITC!

High concentration salt also activates TRPV1, the hot/pain receptor.** When TRPA1 is activated, TRPV1 will usually be inhibited, and vice versa. 

So garlic in your salad dressing or sprinkled on a salty food will help hide the fact that you may have used too much salt...

* Oka, Y., Butnaru, M., von Buchholtz, L., Ryba, N. J. P., & Zuker, C. S. (2013). High salt recruits aversive taste pathways. Nature, 494(7438), 472+.

** Lyall V, Heck GL, Vinnikova AK, Ghosh S, Phan TH, Alam RI, Russell OF, Malik SA, Bigbee JW, & DeSimone JA. (2004). The mammalian amiloride-insensitive non-specific salt taste receptor is a vanilloid receptor-1 variant. J Physiol 558: 147+.

Monday, August 7, 2017

Planning to give a talk about beer flavors for Scott Kerkmans in Brewing Industry Operations Program at Metropolitan State University, Denver, Colorado next month, so I have been looking into how beer is made, and in particular have been interested in the flavors that result from the temperatures at which beer malts are kilned.

Beer malts —left: pale malt; top right: black malt; bottom right: crystal malt. Photo by Lufke, from Wikipedia.
These temperatures range from below 100ºC for pale malts to increasing temperatures above that for darker and darker malts, finally to around 200ºC for black malts. The resulting color goes from pale yellow to dark brown, and the flavors go from grassy and sweet, through nutty for kilning temperatures around boiling, to chocolate and coffee flavors at temperatures up to 200ºC. (BTW, makes me think of the effects of oxidation and heating on teas.)

If you look at the temperature scale below you'll notice that the temperature-sensitive TRP channels in your mouth are activated at temperatures that are about half the temperatures at which these malts are kilned: at lower temperatures the chemicals in the malts tend to activate TRPV3 (warm) and TRPM5 (sweet), while at higher temperatures the kilned malts activate TRPV1 (nutty to chocolate flavors).

Am fascinated by this observation, and eager to figure out what it means — stay tuned!

Thursday, July 27, 2017

Oolong-hai and lychees

Came across this fascinating photo by Chinh Le Duc when searching for tea images on The title words read: "Drink, glass, cocktail, beverage and alcohol."  

Photo by China Le Duc,

Alcohol? When my keyword search was "tea?" What is going on here? 

Come to find out that there is an iced alcoholic beverage called oolong-hai consisting of oolong tea combined with shōchū, a Japanese drink fermented and distilled from any one of a number of starches, including rice, barley, buckwheat, and interestingly, sweet potatoes. Apparently the choice of starch conveys a distinctive flavor to its shōchū. 

Here's what Sara Shacket of the blog Tea Happiness* has to say about the oolong-hai she savored:
"The drink was incredibly refreshing on a hot NYC summer evening. I tasted the slightly bitter earthiness of the Oolong, along with a subtle hint of something smoky that reminded me of whiskey. Shochu has a subtle flavor, and so my drink didn't have the overwhelming alcoholic taste that I usually expect from a cocktail. This makes the drink quite dangerous for me. I hardly even noticed that I was consuming any alcohol! It had a similar refreshing feel to the mugicha I recently tried.  I also love that it wasn't sweet. In fact, the server warned me that it wasn't a 'sweet cocktail'."
At another (commercial) website,** found a good photo of oolong-hai, along with a recipe:

Oolong-hai from
Comparing this photo with the one by Chinh Le Duc, it looks very much the same: same color and cloudiness. 

Which led me to the next question, namely would lychees go well in this drink?

Looked up the chemistry of lychees in a paper by colleagues of mine from Cornell, Peter Ong and Terry Acree.*** Turns out that lychees share a number of flavor-significant compounds with oolongs. Some of these, such as linalool, are found in all teas, but the one that stood out for oolongs specifically is furaneol, aka strawberry ketone, which activates the warm receptor, TRPV3. Another important flavor compound in lychees, and perhaps in some oolongs, is vanillin, which also activates TRPV3.  But most striking is the presence in oolongs of cis-rose oxide, which has a characteristic lychee aroma.**** Put together, oolong and lychee will each expand the flavor of the other.

In case you are wondering, I haven't experienced the drink myself. I lack functional aldehyde dehydrogenase, so become quite sick with very little alcohol, and despite my love for oolongs, I really don't like lychees—and now I know why. Lychees have δ-decalactone, which has a strong flavor of coconut. Can't stand the flavor of coconut, and lychees come across as too coconutty to me. So I am not about to try this drink, no matter how hot it gets this summer. 

But you might enjoy it very much!

*** Ong, P.K.C., and Acree, T.E.. Similarities in the Aroma Chemistry of Gewürztraminer Variety Wines and Lychee (Litchi chinesis Sonn.) Fruit. J. Agric. Food Chem., 1999, 47 (2), pp 665–670
DOI: 10.1021/jf980452j.
**** Sheibani, E., Duncan, S. E., Kuhn, D. D., Dietrich, A. M. and O'Keefe, S. F. (2016), SDE and SPME Analysis of Flavor Compounds in Jin Xuan Oolong Tea. Journal of Food Science, 81: C348–C358. doi:10.1111/1750-3841.13203

Thursday, July 6, 2017

Fresh versus dried fruits

The other day a friend of Pairteas asked me why certain fruits—blueberries, kiwis, and apricots in particular—go better with oolongs when dried than when fresh.

The first point to make is that the chemicals in oolongs for the most part activate the warm to hot receptors. Consequently foods that activate the cool/cold receptors, such as blueberries and apricots, will cause the flavors of most oolongs to disappear.

The second point is that drying, whether of fruit or tea leaves, changes their chemistry. When they are fresh, fruits and tea leaves are still alive, so they respond to drying by making defense chemicals in response to the stress. 

For example, fresh ginger has two chemicals, zingerone and gingerol, that are slightly different in flavor. Zingerone activates the cold receptor (TRPA1) and gingerol activates the hot receptor (TRPV1). As ginger dries, these chemicals disappear or, to be more exact, are transformed into shogaols that collectively activate TRPA1. For those of you who were at our WTE about green tea way back in 2015, you might remember how a tiny bit of dried ginger dampened the bitterness of the tea and brought out its herbaceous qualities.

Apricots have compounds that hit the cold receptors, so can kill the flavor of an oolong.  As apricots dry phenyl ethyl alcohols and linalool oxides oxides appear—they hit the warm/hot receptors and make oolong happy.

As for blueberries, don't know what happens in them specifically. Fresh blueberries hit the cool/cold receptors, as does blueberry jam—the berries don't have a chance to make an abundance of stress chemicals before they are cooked and their enzymes denatured. My guess is that drying makes them create a panoply of chemicals similar to those in apricots.

And as for kiwis—will have to do some experiments once I get settled in my new home...

...and please do experiments yourselves to see what happens. Would love to hear from you!