Brewing Coffee (a Framework)

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What Happens When You Brew Coffee...

When you brew coffee, hot water acts as a solvent, washing the soluble solids out of the coffee grinds and into the brew. If you dissolve table salt in water, you have a soluble solid. Brew methods that use paper filters have only the soluble solids in the cup. Some brew methods also allow insoluble solids to enter the brew. French Press, Espresso or Turkish Coffee are three methods that will have insoluble particulates suspended in the liquid. Insoluble solids will precipitate out of the brew over time, if you don't disturb the liquid. Hence your mug of French Press coffee might taste gritty nearing the end, and there is muddy residue in the bottom of the cup. Suspended solids add a sense of body to the cup, but can also add bittering tastes. Soluble solids are bonded with the water molecules, and will not separate over time.

The 5 main factors that affect your brew:

1. The ratio of water-to-coffee. Most people find that when 20% of soluble solids are extracted from the coffee grounds, the brew has the best flavors. Too much extraction (too fine grind, too long brew time, too hot water, too much coffee in the recipe) and the brew is bitter. On the other hand, under-extraction results in a thin, weak cup. Simply using more coffee grinds cannot fix other brew problems: If you use 20 grams coffee and 350 ML of water and 4 minutes steep time to achieve 20% extraction (it should), using 40 grams coffee with a contact time of 1 minute to compensate will not result in a better cup. We have found that for the most accurate brewing on a manual brew device, it is best to measure your water by weight. You can do this by preparing your coffee on a scale, with a ratio of 1:17 parts coffee to water.
2. The particle size of the coffee: finer grind means more surface area of the bean is exposed to the water. So, for a brew method that uses more dwell time, a courser brew is necessary. This is a tough issue in that there is no real basic home ready equipment with which to measure particle size. One thing that you could do is visit your local roaster or whole bean coffee retailer and ask them to grind you a sample of coffee for the brew method that you most commonly use at home. Grind settings aren't universal, so just knowing the "number" that it was ground on might not help. You can also of course experiment yourself at home until you find the grind that best suits your taste.
3. The temperature of the water, ideally between 198-204 f, since water is a better solvent at near-boiling temperature. This is a major reason why it is always better to brew a full batch on an auto-drip machine, because they are built to get a full batch of water up to the proper temperature. Water temperature retention is also an issue in many manual brewing devices, and is important to keep in mind when you brew.
4. The contact time, how long the water and coffee are in contact with each other. As is mentioned above, this is directly relatable to the particle size of your grind. Courser grinds call for a longer contact time for proper extraction.
5. The agitation, since stirring the coffee-water infusion increases extraction rate of soluble solids. When considering agitation, it is important to remember that simply adding the water to the grounds causes agitation. In many brew methods with a longer dwell time it is important to agitate the brew again during the dwell time.
   

Other factors that have a major impact are:

- The quality of the water; bad tasting water makes for bad tasting coffee. Also, do not use distilled water. The absence of some minerality can lead to very sharp and bitter tastes.

- The quality of the coffee you are using, which is obvious, but also the roast level. Speaking in broad terms, some roast levels perform better in different brew methods. Lighter roasts can taste aggressively bright in brew methods that use longer dwell times and some pour over methods don't really showcase the caramelized sweetness in darker roasts. Of course, brew ratios can address some of these issues.

-The cleanliness of the brewing equipment. Old sediments easily make for rancid flavors in the cup. A good rule of thumb is if you smell an odor from your coffee making equipment, clean it. If you cannot remember the last time you cleaned your brewer, clean it.

The ideal brewing practice is:

• Grind immediately before you brew.
  
• Adjust grind to brewing method and use a good grinder.
• Use good clean water. If your water does not taste good, neither will your coffee.
• Pre-Rinse your paper filter. This reduces paper taste, which can be more of an issue when brewing small amounts of coffee.
• Make more. For a somewhat mysterious reason, filter-brewed coffee tastes better the more you make.
• Coffee is fresh for 10 minutes or less. Try to make the right amount of coffee so you are drinking fresh brewed coffee more often.

Here are some ideal coffee/water/time ratios for different brewing methods: