coffee - reactions ever since we totally nailed sliced bread,humans have been trying to create the perfect cup of coffee. why’s it so hard? becausethere’s a ton of complex chemistry involved. [splash] we all know and love coffee for the caffeine,but caffeine doesn’t really affect its flavor.
dark roast coffee has more caffeine, making awesome-tasting coffee requires excellencein three parts: the bean, the roast, and the brew. let’s break it down. the bean coffee farmers devote a lot of time and energyinto growing and harvesting coffee trees.
that’s right -- coffee does grow on trees.the bean is actually the pit of a coffee cherry -- after these cherries get pitted,the beanis dried and processed. for the best-tasting coffee, go for (uh-rab-icka) arabica beanssince they have a higher taste quality and a wider variety of flavors and aromas. ifyou’re looking for an extra jolt, robusta beans have twice as much caffeine. (reactionspro tip! (™)): buy coffee in one-way valved bags that let gases out but don’t let oxygenin, keeping coffee fresher longer. and because freshness is key, buy whole beans, not pre-ground,and use them asap. the longer the beans sit, the staler your brew will be fresh beans have lots and lots o f compoundsthat determine how great your coffee tastes.
take (klor-oh-jenn-ick) chlorogenic acids:once roasted, these acids react to form a variety of different products that all affectaroma and flavor. which brings us to… the roast roasting coffee beans draws out flavors likefloral notes, chocolate and more (onscreen: molasses, earth, caramel, cloves, and acidity)in a multistep, heat-related process. first[at 150-200 dc], there’s the maillard reaction,which may be the world’s most delicious chemical â reaction. during this reaction, sugars and proteinsreact to form aroma and flavor compounds. maillard chemistry is partially to thank forthe great smell, browning, and flavor of other
foods like steak, fries, and, of course bacon.it also creates lots of compounds in coffee, including 2-furfurylthiol (2-fur-fur-ill-thigh-all),which gives coffee its delicious roasted flavor. as the temperature rises [onscreen: 170-200dc], caramelization takes place -- sugar is caramelized and the generated compounds createbutterscotch (diacetyl) and burnt sugar (furanones) flavors. at 205 dc, the water inside the beanvaporizes, causing the bean to expand and crack open -- what’s known as the “firstcrack†in the coffee industry. (noel posted a video of this on slack.) (visual: brownoval + circle of blue inside that expands into a cloud and cracks the bean as it expands.leads to “flavor†explosions) “light roast†coffees are taken out of the roasterafter this first crack. light roasts are higher
in acidity and the characteristics of differentbean origins are most pronounced in light roasts. so that origin better be good. at 225-230 dc, the bean cracks again -- the“second crack.†this crack results from the cellulose in the bean’s cell walls breakingapart. as it gets hotter, the bean turns a darkerbrown for that crowd-pleasing medium roast. medium roasts create a coffee that has goodbalance between acidity from the bean and body from the roasting chemistry. aromaticcompounds emerge that give coffee an earthy scent and earthy, roasted flavors. even more heat will turn the bean darker andit’ll become pretty oily -- that’s when
you get a dark roast. by then almost all thetasting notes are from the roasting. you can’t really tell the bean origin at this pointbecause the strong body overwhelms those geographic notes -- dark roasts are often used for espresso. so you’ve got all those choices lined upin bags on the shelf. but how do you actually brew the best coffee you can?? the brew and now we’ve arrived at the weakest link,the part too often left to us amateurs. so you’ve got a bean with a great originstory and a roast you prefer. just grind it up and add hot water, right? â unfortunately,you can have the highest quality, best roasters
and growers beans, and still mess up coffee. there are several key components: there isthe coffee: water ratio. the pros say skip the tablespoons and get a scale. then thereis water quality: the flavor of the water will dramatically affect the flavor of yourcoffee. so the pros use filtered or bottled water.and there is water temperature: get it close to 96 dc (205 f), but not over. boiling wateris too hot and you’ll get gross burnt coffee. so now you’ve got to decide how to brewit. there are [show pics] mr. coffees, percolators, pourovers, french presses, and chemexes. thebasic principles of all brewing methods are the same:
as you add water, it spreads across the groundsand co2 bubbles out. once the grounds are soaked, the extra hotwater will dissolve compounds found in the beans’ roasted cells. most of the deliciouscompounds dissolve in water more readily than the nasty ones, so add enough water to getthe good stuff to dissolve, but, not so much that your coffee tastes… gross. and finally,diffusion. osmosis drags those compounds out of the coffee grounds and into the water -- bringingthose great flavors into your coffee pot. the pros will tell you that pour-over methodslike a chemex are better than automatic coffee makers. there’s more control over thingslike how much water gets added and when. and pour-over methods continuously replenish thecoffee grounds with fresher water, which makes
the brew go faster. it’s also an all-in-onestream, instead of the shower-head-like contraption in your coffeemaker.
sooo… what’s your preferred method formaking your favorite cup of coffee? or perhaps it comes down towhat you add in your cup. i prefer my coffee with some whiskey and cream.let us know how you prefer your coffee in the comments below. and as always, thanksfor watching.
