{"id":31,"date":"2018-02-27T23:43:00","date_gmt":"2018-02-27T23:43:00","guid":{"rendered":"http:\/\/under-belly.org\/?p=31"},"modified":"2022-05-27T18:51:43","modified_gmt":"2022-05-27T18:51:43","slug":"ice-cream-flavor-coffee","status":"publish","type":"post","link":"https:\/\/under-belly.org\/ice-cream-flavor-coffee\/","title":{"rendered":"Ice Cream Flavor: Coffee"},"content":{"rendered":"
[Edited 9-17-2020 to adjust ice cream cooking time\/temperature]<\/div>\n
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Welcome to the first post that focusses on a single flavor. We\u2019re starting with coffee, not because it\u2019s simple\u2014it\u2019s maybe the most complex flavor we\u2019ll have the pleasure of disecting. We\u2019re going to take on this complexity because coffee flavor illustrates so many principles, and because there\u2019s a mountain of high quality research already available, at least with regards to making a cup of joe.\u00a0<\/div>\n
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To make good coffee ice cream you do have to learn to make good coffee. If this were a simple task, everyone would be doing it. Everyone is not doing it. I lived in New York City for about 15 years before having my first truly good cup. Coffee\u2019s 3rd wave took a couple of decades to make it all the way East from Portland and Seattle, and is only just now gaining traction in a culture that\u2019s been long-steeped in the bitter seas of Starbucks, and before that, street-cart swill and Caf\u00e9 Bustello.<\/div>\n
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Good coffee starts with sourcing high-quality beans that are roasted with precision and that have whatever characteristics you most enjoy. Differences in regional varieties and processing methods are beyond our scope here. See the links at the bottom for suggested reading.\u00a0<\/div>\n
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Roasting, however, is of primary importance and needs to be considered. Roasting coffee well is hard. I\u2019ve bought coffee beans from many local, supposedly artisanal roasters, and have usually been disappointed. Sometimes the roasters just have terrible ideas about coffee. Many of these ideas were propagated by Starbucks and other 2nd wave roasters\u2014like the idea that dark-roasted coffee is somehow \u201cbolder\u201d or more serious than light and medium roasts. Dark-roasted coffee is, more often than not, ruined coffee. Once you inch past a full-city (medium-darkish) roast, the aromatic flavors that distinguish good beans from bad ones, and one region from another, are muted, replaced by generic roasted flavors. Roast \u00a0darker still and those origin flavors are demolished entirely, replaced by burnt flavors and bitter non-volatile chemicals.\u00a0<\/div>\n
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Selling us on dark roasts was a cynical ploy by companies like Starbucks, who figured out that 1) if you roast the coffee dark, your customers won\u2019t be able to tell the difference between good beans and bad, from this region or that one, from beans harvested this season or last. So quality and consistency become non-issues. And 2) if you roast the coffee dark, it will be bitter, and people will want to tame it with sugar and milk. Which means that instead of selling $1 coffees or $3 espressos, you can sell $5 latt\u00e9s and skim-mocha frapuccinos and other coffee-flavored sundaes that can survive bad ingredients and poor technique, and, (bonus!) will let you to mark up milk for a 1000% profit.\u00a0<\/div>\n
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Even roasters who attempt proper degrees of roasting often mess up. Because the process is much more complex and sensitive to precise timing and energy-input modulation than, say, baking bread or popping popcorn. And it’s easy to let portions of some of the beans roast more than others. This may lead to coffee that has the overall color and aroma of a proper roast, but upon closer examination will have spots that glisten with oils brought to the surface. The resulting coffee will typically have the basic character of a light or medium roast, but will have burnt \/ bitter background notes that will always be out of balance. Every attempt at a light or medium-roast coffee I\u2019ve bought from Whole Foods\u2019 in-house roaster has suffered from this. Same with coffee bought from most small shops that roast their own. In the end, looking at the beans only gets you so far. To know for sure you have to taste the coffee.<\/div>\n
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Not living in the Pacific Northwest, I\u2019ve been limited to a handful 3rd wave companies who have built outposts here, and to a very small number of local roasters who know what they\u2019re doing.\u00a0<\/div>\n
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Some of the nationally-distributed roasters that I like:<\/b><\/div>\n
-Stumptown (Portland \/ NYC)<\/div>\n
-Intelligentsia (Chicago)
\n-Toby\u2019s Estate (Australia)<\/div>\n
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Some NYC roasters that get it right:<\/b><\/div>\n
-9th St. Espresso<\/div>\n
-Joe the Art of Coffee<\/div>\n
–Coffee Mob<\/a> (in my neighborhood. The only indy shop I\u2019ve been to that roasts like a genius).<\/div>\n
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I like to buy single-origin beans, because they’re usually the most interesting. Even with espresso (a glorious topic that lies well beyond our scope, because the espresso process doesn\u2019t lend itself to ice cream) baristas have figured out how to work with single origin beans, which were previously believed to be too full of character and fruity acidity to make a balanced shot. Nowadays there\u2019s less reason than in the past to fall back on blends.<\/div>\n
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I also like to look for direct trade arrangements between the roaster and the farmer. Coffee has historically been rife with colonial exploitation, so it\u2019s gratifying to see roasters working with individual farmers and cooperatives, ocassionally even investing in their operations and helping the farmers work toward prosperity and independence.<\/div>\n
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My favorite coffees are often from East Africa, especially Ethiopia, where coffees often offer a magical balance o fruity acidity and floral or herbal aromas. It’s especially a treat when I can find natural-process versions (which are dried in the sun, allowing some fermentation), which can add more body more complex, darker fruit notes. I like a lot of flavor in my cup.\u00a0<\/div>\n
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People who don\u2019t want so much flavor generally tame their coffee with milk and sugar. I do not, unless the coffee is bad, or I\u2019m enjoying a morning capuccino (which is a whole \u2018nuther topic). This introduces the basic problem of coffee ice cream\u2014there\u2019s going to be a lot of milk and sugar. Because ice cream. So if you want those coffee flavors to stand up, you\u2019re going to have to put a lot of them in there to begin with, especially the acidic and aromatic flavors that will be most muted. We\u2019ll get to this.<\/div>\n
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But first\u2014how to make a good cup of Joe?<\/h4>\n
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Brewing coffee is an extraction process. We\u2019re extracting literally hundreds of compounds from the coffee beans, including the basic sugars, acids, and alkaloids that constitute the heavy molecules detected by our taste buds, and also the myriad volatile organic compounds that we detect with our nose. There are other compounds that we either don\u2019t want, or that we want in minute quantities. And among the ones that we do want, we want them in proportions that taste balanced and satisfying. And we want the overall flavor to be strong enough. But not too strong.\u00a0<\/div>\n
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How do you do all that? Happily, there\u2019s science on the topic. Which means that some very patient men and women with PhDs have done much of the work for us. Here\u2019s a chart from the Specialty Coffee Association of America:<\/div>\n
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\"Coffee<\/a><\/p>\n<\/div>\n

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There\u2019s a lot of information here for a 2-dimensional chart. Allow me to summarize. The two axes represent strength (vertical axis) and solubles yield, or extraction (horizontal axis).\u00a0<\/div>\n
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Strength is simply the amount of coffee solids disolved in the brewing water, represented as a percentage of the water weight. More = stronger.\u00a0<\/div>\n
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Solubles yield is what percentage of the available soluble stuff you’ve drawn out of the beans. Brewing for a longer time, or with a finer grind (which exposes more surface area) gives more extraction.<\/div>\n
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If you extract too little, you have an \u201cundeveloped\u201d cup, which is typically sour and thin. If you extract too much, the coffee becomes bitter.<\/p>\n

The diagonal red lines are each for a brewing ratio, which is the actual ratio of coffee beans to water. The lines are diagonal because as you brew longer, or hotter, both strength and extraction of the coffee increase. You control these variables independently by choosing different brewing ratios.<\/p>\n<\/div>\n

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For both strength and extraction, there\u2019s a sweet spot, represented by the orange square in the middle. According to the chart, you can get into that zone with any brewing ratio between 1:15.5 and 1:19.5. This can also be represented as 4.8% and 6.3% relative to the weight of the water.<\/div>\n
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Without a coffee refractometer, it will difficult to follow this chart precisely. And there\u2019s no need to. Use the chart as a model, to help you understand what you\u2019re tasting, and which variables you need to change when trying to adjust the flavors. If your ideal cup doesn’t land precisely in that square, who cares.<\/div>\n
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The chart does not address the specific factors that determine extraction, which are time, temperature, and grind size. Time and grind size are bound together; the coarser the grind, the more time you need to get to a particular level of extraction. Many coffee making methods determine the general grind size. Press pots require a coarse grind (and so a long brew time) otherwise you’ll clog the filter. Espresso requires a very fine and consistent grind. Drip and pourover coffees cede the control of time to gravity and physics, so you have to find a grind size that works with the time you’re given. See notes on grinding, below.<\/p>\n

Temperature is also critical. It affects extraction rate, but does not affect all flavor compounds equally. So brewing temperature is an important variable for adjusting the flavor balance. The generally accepted range of brewing temperatures is\u00a0 90\u00b0C\u201396\u00b0C \/ 195\u2013205\u00b0F.\u00a0<\/p>\n<\/div>\n

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Within this range, higher temperatures will give more extraction, more body, more sweetness, more bitterness, and less acidity. Lower temperatures, or course, will give thinner body, more acidity, less bitterness, and less sweetness. Based on my personal experiments, I brew French press coffee at 93\u00b0C \/ 199\u00b0F. I use a higher temperature for coffee ice cream. More on that later.<\/div>\n
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What about cold brew? I’ve now had some good-tasting examples, but more often than not find that it’s pretty dull. I believe it\u2019s popular because people are accustomed to bad coffee that tastes burnt and bitter. Cold brew extracts fewer bitter alkaloids from the bean, so without any special skill or even decent quality beans, you can entirely avoid bitterness. But cold brew also results in reduced acidity and aromatics\u2014there\u2019s less there there. More bass notes and roasted flavors. Coffee shops have turned \u201clow acidity\u201d into a feature, not a bug, because consumers don\u2019t know what acidity is. It sounds scary, and is easy to conflate with bitterness, even though it\u2019s essential to a balanced and lively cup. Acidity and bitterness, in fact, have a reciprocal relationship in hot-brewed coffee. More of one leads to less of the other.\u00a0<\/div>\n
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When making coffee ice cream, we\u2019re interested in increasing acidity and aromatics, not decreasing them. We need to try to punch through the heavy muting tendencies of the dairy and sugar.\u00a0<\/div>\n
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Notes on grinding<\/b>: If you want good coffee, you need a good burr grinder. This means a grinder with a hopper on top for beans, a set of conical or flat burs to grind the coffee, and a receptacle for grounds on the bottom. A whirly-blade grinder gives no consistency, so you are you are guaranteed some mix of coffee dust in with your grounds, which will over-extract and cause bitterness. If you\u2019re just making brewed coffee and ice cream, any decent burr grinder will do. Entry-level grinders from Baratza<\/a> will make as good a cup of brewed coffee as anything (if you\u2019re making espresso\u2014again, beyond our scope\u2014you don\u2019t need a good grinder; you need an awesome grinder. You will spend over $700 or you\u2019re wasting your time. More reason to just go to the caf\u00e9).\u00a0<\/div>\n
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Your coffee needs to be fresh, meaning roasted between 4 and 10 days ago, stored in an airtight container at room temperature, and ground right before use. If you\u2019re buying pre-ground coffee and letting it sit around for days, you\u2019re sabotaging the process before you even begin.<\/div>\n
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A Coffee Recipe<\/h4>\n
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For reference, here\u2019s my idea of good coffee, scaled for a large French press pot (this is a full-immersion process that’s similar to what works well in ice cream):<\/div>\n
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-1400g filtered water<\/div>\n
-80g\u201390g coffee. A good, fresh, light-to-medium roast. Medium-coarse ground, right before brewing (I don\u2019t know how to measure grind precisely. I go a few clicks finer than the coarsest press pot setting. You\u2019ll have to experiement) Concentration: 5.7%\u20136.4% by weight.<\/div>\n
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-boil the water<\/div>\n
-put coffee grounds in prewarmed pot<\/div>\n
-let the water cool to\u00a0 93\u00b0C \/ 199\u00b0F (for some natural process coffees, I go as low as 90\u00b0C \/ 195\u00b0F). an easy way to do this is to pour the water into a pitcher or measuring cup, and stir while watching a digital thermometer.\u00a0<\/div>\n
-fill press pot about 3\/4 full. start 4-minute timer.<\/div>\n
-after 45 seconds, stir vigorously to break up the foam and raft of grounds on top. chopsticks or a palette knife work well.<\/div>\n
-fill the rest of the way. cover.<\/div>\n
-brew 4 minutes total and press the plunger.<\/div>\n
-immediately drink or decant to cups \/ a prewarmed thermos.<\/div>\n
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Note on brewing methods: I use a press pot, because I like a lot of body, and because I like the control it gives over every variable. Many other brewing methods are capable of equally good, but different results. Some methods, like percolation, are not capable of good results.\u00a0<\/div>\n
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You’ll have to experiment to get the grind right. If your coffee tastes thin and sour, go finer. If it tastes bitter, ashy, or astringent, go coarser.<\/div>\n<\/div>\n
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If you measure with sieves or with an app,<\/a>\u00a0you’ll probably find the right median ground size to be between 0.8 and 1.2mm. The better your grinder, the finer you’ll be able to go.<\/div>\n
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SCAA Flavor Wheel<\/a><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n
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Finally, Coffee Ice Cream<\/h3>\n
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It took 21 versions to get this right. The goal was to preserve the full spectrum of flavors and aromas I get from a great cup of brewed coffee (like from the above method) or from a great cup of espresso, and to somehow have it complemented by, not demolshed by, the sugar and dairy of the ice cream.\u00a0<\/div>\n
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\n<\/b>Some of the challenges:<\/b><\/div>\n
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