Brew
the crucial factors to make your coffee
brewing is simply the process of using hot water to extract different compounds from roasted coffee (including caffeine and different flavor qualities)
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initial extraction: caffeine, fats, acids (body, sour)
more extraction: sugars (sweet)
even more extraction: carbohydrates (bitter)
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good coffee is the result of finding the sweet spot with balanced extraction - here are some important factors to be mindful for a proper brew
one crucial aspect of brewing coffee properly is also the easiest to control:
the coffee-to-water ratio by weight (typically between 1:14 to 1:17, depending on the brew process)
WHY?
to clarify, that’s the ratio of coffee to water you pour in, not what you get out (which would be “yield”)
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these ratios are agreed on by the industry to optimally extract the great flavors of coffee without the harshness
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think about it from the extremes: too little water means under-extraction; too much water means over-extraction
SO... WHAT'S THE RATIO?
you’ll have to do some research specific to your chosen brew method, but some examples are:
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for brews by immersion (French Press, Aeropress), aim for a more concentrated ratio like 1:14 (e.g. 20 g coffee, 280 g water)
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for brews by drip process (pour overs, Chemex), use something less concentrated like 1:16-1:17 (e.g. for 40 g coffee, 640-680 g water)
another way to consistently extract your coffee is also easy to control:
the amount of time you take to brew your coffee
WHY?
this is probably much more intuitive: the more time you brew coffee with hot water, the more it is extracted
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like the coffee-to-water ratio, the brew time is specific to your chosen brew method (i.e. different for French Press vs. Chemex)
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do some research on the different “recipes” for what brew times to start with as you experiment
DRIP PROCESS CONSIDERATION
when brewing by a drip process, the flow of the water pouring through the coffee is sensitive to the brew temperature and grind sizes (more on those subjects next)
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the water will flow through faster at higher temperatures and coarser grind sizes (due to lower viscosity and wider flow paths respectively)
CAN I PLAY WITH BREW TIMES?
once comfortable with the fundamentals, you can adjust the brew time (with brew temperature and grind size) to balance your preferred flavors
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note that experiments have shown that caffeine is mostly extracted in the earlier portions of a brew (e.g. first third of espresso pulls, or first couple of minutes of pour overs)
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so caffeine content will be relatively stable with as you adjust brew times (within reason)
this one is less straightforward and may take some trial and error based on taste:
depending on the roast level, start off with water at 195-205°F / 90.6-96.1°C (hotter for lighter roasts, colder for darker roasts)
WHY?
to optimally extract the right flavors from ground coffee, there is a sweet spot in brewing temperature
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water that is too cold won’t extract the good flavors in coffee enough
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water that is too hot (say boiling) will bring out the harsher and bitter (i.e. unwanted) flavors of coffee
ONE TEMP DOESN'T FIT ALL
the ideal brewing temperature should depend on many factors
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for example, lighter roasts (which are more difficult to extract) call for hotter water, compared to colder water for darker roasts (where the harsh, bitter flavors may be extracted more easily)
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my suggestion: brew the first batch at the suggested temperature for the roast level, then adjust future brews hotter for more flavor or colder less harshness
NOT JUST THE COFFEE
your brewing method will probably need some kind of vessel (such as a French Press or Chemex) to hold the grounds as well as the brewed coffee
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it’s important to pre-heat the vessel with the hot water, then pour it out just before adding grounds
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that’s because if this vessel is cold before the brew, it will absorb the heat from (and even shock) the brewing coffee, effectively making the brew colder than intended
with the coffee-to-water ratio, brew time, and brew temperature (mostly) relatively constant:
the coffee grind size is where there’s most room to play and tune your brew
WHY?
again, this comes down to extraction
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finer grind sizes (for a given amount of coffee) increases the total surface area for water to contact and extract the compounds that make up the coffee flavor
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this means finer grinds will go through extraction more quickly than coarser grinds (i.e. less time needed)
SO... WHAT GRIND SIZE DO I USE?
just like the coffee-to-water ratio and brew time, this depends on the brew process
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coarser grinds are typical for French Press, whereas finer grinds are used for Moka Pot or pour over brewing
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my suggestion: look up recommended size ranges for the process, start in the middle of the range, then adjust for more or less extraction (this will take some playing with alongside the brew temperature)
this step might be less known to new brewers, but is an incredibly important part of the brewing process:
let the coffee bloom at the beginning of the brew
WHY?
blooming is when you pour enough hot water into the coffee grounds at the beginning of the brew to get it all wet
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this helps to release CO2 trapped in the coffee from the roasting process (you’ll see the bubbles form and escape)
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as mentioned in “Freshness”, the CO2 creates a barrier between the water and coffee, preventing proper extraction
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the aim is to get rid of much of the CO2 during this beginning stage, so the rest of the brew can go uninterrupted
HOW?
a good starting point is to pour twice the amount of hot water as their is coffee (1:2 ratio) to bloom
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if you didn’t manage to get the full coffee bed water, it’s okay to stir it a little to saturate all the grounds
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let the coffee bloom for 30-45 seconds (longer for more freshly roasted coffee where there’s more CO2 to release)
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you can tell if it needs more time as the CO2 bubbles continue to release