Any in-depth analysis of specific hop varieties and their essential oils will display landscapes of terpenic content within. By getting to know terpenes and the flavors and aromas that they suggest, you can make informed decisions not just about which hop varieties suit the tastes of your friends and customers, but which other ingredients you can choose to employ when crafting beers that will beguile and surprise them. Given the prevalence of hop character in IPA, even those that include the additional ingredients that we examine in this book, terpenic relationships between combinations of hops as well as between hops and the additional non-hop ingredients are what will likely make or break these beers.
Such in-depth analyses can show both the larger terpenic building blocks of a particular hop variety’s character and the trace amounts that nudge it in various distinct directions. Nor do all hops carry the same overall oil content—pound for pound, you can extract more essential oils from some varieties compared with others. This is only one of many reasons why particular hops are suitable for particular uses, bittering, say, or as a late addition; it also presents hops through a prism with which the brewer of eclectic IPAs can make choices of both logic and artistry.
Casting an analytical eye across the profile of essential oils in hops may on the surface show particular hop varieties relatively high in one thing while low in another, perhaps indicating vast differences in effect. But if one takes a look at some of the terpenes concerned, the lack of one thing may be nearly compensated for by greater content of another, once one has evaluated the sensory terrain. In other cases, however, a doubling of those trace compounds can indicate enormous differences. As with so many things, it’s all about balance and what you prefer. Spend a little time on the websites of any comprehensive hop vendor and you’ll see what I mean.
The following terpenes are those most commonly measured and otherwise evaluated in beer. Each is followed by a list of fruits, herbs, and (here and there) other substances in which they occur. I rely heavily on the information available on the website of the Good Scents Company (http://thegoodscentscompany.com). Many of these lists are long. They are also repetitive, duplicating many, even dozens, of the same natural occurrences from terpene to terpene. Think of reading through them as like listening to passages of music, variations on themes that, though composed of essentially the same elements, can create vastly different effects and moods.
Alliums, banana, cayenne, clove, ginger, guava, laurel, lemongrass, marjoram, oregano, pepper (black), saffron, strawberry
Allspice, angelica, anise, basil, bay laurel, bergamot, blood orange, caraway, cardamom, carrot, cassia, celery, cinnamon, citronella, clove, coriander, cumin, currant, cypress, dill, eucalyptus, fennel, frankincense, galangal, ginger, grapefruit, guava, hyssop, juniper berry, lavender, lemon, lime, lovage, mandarin, mango, marjoram, nutmeg, orange, oregano, parsley, parsnip, pepper (black), peppermint, pines, plum, pomelo, rosemary, sage, spearmint, tamarind, tarragon, thyme, tomato, turmeric, valerian, wormwood, yarrow, yuzu
Cinnamon, galangal, juniper berry, lavender
Apple, basil, bay leaf, bergamot, blood orange, carrot, chamomile, cubeb, gardenia, ginger, grape, grapefruit, guava, jasmine, lavender, lemon, lime, mandarin, nutmeg, orange, oregano, pear, pepper, spearmint, tea, thyme, witch hazel, yuzu
Apple, apricot, basil, bay laurel, bergamot, blackberry, blood orange, blueberry, boysenberry, cardamom, carrot, chamomile, cinnamon, citronella, clove, coriander, cumin, currant, cypress, dill, eucalyptus, fennel, frankincense, galangal, ginger, grapefruit, guava, hyssop, juniper berry, lavender, lemon, lime, lovage, mandarin, mango, marjoram, nutmeg, orange, oregano, parsley, parsnip, pepper (black), peppermint, pines, plum, pomelo, rosemary, sage, spearmint, tamarind, tarragon, thyme, tomato, turmeric, valerian, wormwood, yarrow, yuzu
Allspice, almond, basil, bay laurel, bergamot, blood orange, cardamom, carrot, celery, chervil, cinnamon, citronella, coffee, coriander, fig leaf, frankincense, geranium, gin, ginger, grape, grapefruit, jasmine, lavender, lemon, lemongrass, lime, lovage, mace, mandarin, marjoram, mustard, narcissus, nutmeg, orange, oregano, pepper (black), peppermint, plum, rose, rosemary, rum, sage, savory, tangerine, thyme, tomato, verbena, white wine, wormwood, yuzu
Allspice, angelica, anise, artichoke, basil, bay laurel, bergamot, blood orange, cardamom, carrot, cassia, celery, cinnamon, citronella, clove, cubeb, currant, curry leaf, cypress, eucalyptus, fennel, firs, galangal, geranium, ginger, grapefruit, guava, hyssop, juniper berry, lavender, lemon, lemongrass, lime, mandarin, mango, marjoram, nutmeg, orange, oregano, parsley, pennyroyal, pepper (black), peppermint, pines, raspberry, rosemary, sage, spearmint, tamarind, tea, thyme, tomato, turmeric, valerian, witch hazel, wormwood, yarrow, yuzu
Anise, caraway, cardamom, dill, fennel, pepper (black), peppermint, pines, sage, spearmint, tea tree oil
Allspice, angelica, anise, apple, apricot, basil, bergamot, blood orange, blueberry, butter, cacao, caraway, cardamom, carrot, cassia, celery, chamomile, cherimoya, cherry, cinnamon, citronella, clove, coriander, cranberry, cubeb, cumin, currant, curry leaf, dill, elderflower, eucalyptus, fennel, fig, frankincense, galangal, gardenia, geranium, ginger, grape, grapefruit, guava, hyssop, jasmine, lavender, lemon, lemongrass, lime, lovage, mace, mandarin, marjoram, nectarine, nutmeg, orange, oregano, papaya, parsley, patchouli, peach, pennyroyal, pepper (bell), pepper (black), peppermint, pines, pineapple, rose, rosemary, saffron, sage, spearmint, strawberry, tamarind, tarragon, tea, thyme, tomato, turmeric, valerian, wine, wormwood, yuzu
Allspice, angelica, anise, apricot, basil, bay laurel, bergamot, blood orange, blueberry, capsicums, caraway, cardamom, carrot, cassia, cayenne, celery, chamomile, cinnamon, citronella, coffee, coriander, cubeb, cumin, currant, curry leaf, cypress, dill, elderflower, eucalyptus, fennel, firs, galangal, geranium, ginger, grapefruit, guava, hyssop, juniper berry, lavender, lemon, lime, lovage, mace, mandarin, marjoram, nutmeg, orange, oregano, papaya, parsley, pepper (bell), pepper (black), peppermint, pines, pomelo, rosemary, saffron, sage, spearmint, tamarind, tangerine, tarragon, tea, thyme, verbena, wormwood, yarrow, yuzu
Basil, basswood, bay laurel, bergamot, blood orange, blueberry, cardamom, carrot, cinnamon, citronella, coriander, currant, curry leaf, elderflower, eucalyptus, geranium, ginger, grape leaf, grapefruit, hyssop, jasmine, juniper berry, lavender, lemon, lime, mandarin, myrrh, nutmeg, orange, oregano, peppermint, plum, pomelo, rose, rosemary, sage, tamarind, tarragon, thyme, turmeric, witch hazel, wormwood
Lest you get too comfortable with the subject of hop tie-ins with terpenes, we should consider a few other substances. When putting together recipes for well-hopped beer, and eclectic IPAs in particular, an understanding of the constituent aromas, flavors, and other perceptions is helpful. Contributing flavor compounds are legion in beer, of course; they are what makes variety endless and, we hope, endlessly enjoyable. Like knowing which essential oils occur in which fruit, herb, or whatever for the sake of finding a hop variety appropriate for dual use in your IPA, for a similar reason it is a good idea to consider some of the other substances that occur in the process of brewing and fermentation.
All this having been said, it’s a bit of an intellectual exercise to assign quantitative weight to the words and assessments used by sensory experts to describe cognate flavors and aromas in beer. It can be important, for evaluative purposes, to be able to offer these descriptions and to identify naturally occurring substances, but what makes a good beer is the sense and sensibility of a good brewer, one who possesses the associative instincts to govern choices regarding concept, ingredients, and process. Like the lists of naturally occurring terpenes already covered, the following basic information is provided as a sort of shadow on the wall: something to think about, but not necessarily the decisive word when formulating your recipe.
Esters in beer are the aromatic result of alcohol and fatty acids coming together in chemical combination. They can be subtle and lovely, but in excess can be dominant and the sign of undisciplined process. Some beer styles are closely identified with the occurrence of particular esters. In general, ester production is dependent on wort oxygenation, fermentation temperature, starting gravity, and length of maturation. The following are among brewing’s most common esters.
Thiols, also known as mercaptans, are organosulfur compounds where sulfur stands in for oxygen in the hydroxyl group of alcohol. Many thiols carry unpleasant connotations: skunk musk, strong garlic, and the substance added to odorless natural gas to aid in identifying leaks. The fracking fields of today can be sadly redolent of mercaptan. Other, gentler ones embody pleasant fruit flavors that when occurring in fermentation can add a nice touch to the types of beer we consider in this book. A few thiols of the latter type follow.
Thioesters are the result of esterification between carboxylic acid and a thiol (once more with sulfur taking the place of oxygen), and of fatty acid metabolism. Their contribution to beer flavor can be all over the map depending on concentration, and hence can suggest boiled beef, strawberry, melon, or coffee all in a single package.
Lactones are often considered in the use of wood in aging beers, and show up as the coconut constituent of oak flavor. They also occur in the musk-like oil of angelica root as well as in celery, lovage, and sweet woodruff.
Like esters, aldehydes are common aroma compounds used in the formulation of perfumes. Aldehydes occur naturally in anise, cedar, cilantro, cinnamon, citrus, and many flowers such as rose, jasmine, iris, honeysuckle, and lily of the valley. While some common aldehydes, such as formaldehyde and acetaldehyde, would be considered unpleasant accents in beer, some can suggest the warmth and richness of oak due to vanillin and the buttery/caramel elements inherent in furfural.