Brewing
The science of brewing coffee should never sideline the art of serving coffee--even if you are only serving it to yourself. Coffee is experience, and like many experiences, the finer points matter. We hope that through the blog posts, videos, shared stories and other conversations we make available to you, that you will continually improve your artistic ability to create memorable coffee experiences.
In the meantime, there's something to be said for nailing the perfect brew--and doing that consistently. The basics of dealing with that are below.
Make Beans About the Water
It all starts with water. Seriously.
A cup of coffee is made up of almost 99% water so overlooking this key ingredient can unravel all your passionate effort to produce something special; too often this simple step is overlooked or taken-for-granted.
If your tap water is less than ideal or you suspect it may be, we urge you to consider brewing with bottled water. If you really don't know how your water is working for you, a side-by-side comparison is a worthwhile exercise. Prepare the same coffee, identically, using your home tap water and bottled water and see what you discover. You may be surprised.
Finding an appropriate bottled water can be a little tricky since bottled waters are typically designed to be great tasting drinking water (meaning, there are things in the water to make it taste pleasant and refreshing, but those “ingredients” are not necessarily designed for coffee brewing).
For taste characteristics, most bottled waters align around opposing ends of the spectrum, either having very heavy or very light mineral content (alkaline v. acidic, respectively). Again, based on your preferences, these are great waters to drink, but quite possibly not ideal for coffee extraction. Jim Schulman in his well known, Insanely Long Water FAQ, recommends Volvic or Crystal Geyser Natural Alpine water for coffee brewing and, in particular, for espresso machines to minimize scaling/limestone deposits.
Water Hardness
Water hardness is a measure of mineral content, mainly calcium carbonate. Instances of hard water can be seen in home environments where white “scale” buildup can occur in faucets, tea kettles, hot water heaters, etc. Homes outfitted with water softeners are designed to counteract these problems. While some mineral content is desirable in water for coffee brewing, water that is too saturated with minerals will be less effective in extracting the soluble components in coffee, failing to produce the best cup possible. And, as noted above, hard water can corrode and damage coffee brewing equipment.
Relatively inexpensive TDS meters can measure “total dissolved solids” in your water supply and give a clear picture of what you’re up against. Again, getting the water right is a crucial factor in good coffee.
The below chart is the water standard for coffee brewing, published by the Specialty Coffee Association (“SCA”).
| Characteristic | Target | Acceptable Range |
|---|---|---|
| Odor 1 | Clean/Fresh, Odor free | |
| Color 2 | Clear color | |
| Total Chlorine | O mg/L | |
| TDS 3 | 150 mg/L | 75 - 250 mg/L |
| Calcium Hardness | 4 grains or 68 mg/L | 1-5 grains or 17 mg/L - 85 mg/L |
| Total Alkalinity | 40 mg/L | At or near 40 mg/L |
| pH | 7.0 | 6.5 - 7.5 |
| Sodium | 10 mg/L | At or near 10 mg/L |
- Odor is based on sensory olfactory determination.
- Color is based on sensory visual determination.
- TDS measured based on 4-4-2 conversion.
The "Target" is the most desirable point in the Acceptable Range, although falling within the range is considered meeting the standard. These variances are in place to take into consideration real world circumstances, and the target gives the optimum measurement of each characteristic to strive for.
For details of testing equipment & protocols, please see the SCAA Water Quality Handbook.
Read more on water standards at SCAA
Water temperature is another critical variable and is discussed below.
Consistency
Relatively small variances in how you brew coffee can significantly affect how it tastes. This can be noticed from one brew session to the next as in, "why doesn't this cup of coffee taste the same as yesterday, even though I am using the same coffee beans?"
Brewing coffee is all about using water to extract organic and inorganic compounds from roasted coffee into a drinkable elixir. This is called, extraction, and the things that influence it are: quantity of ingredients (water and coffee), grind size, water temperature, brew method and time.
Weigh Everything
Buy an inexpensive kitchen scale to accurately (and consistently!) measure how much coffee and water you use. Any type of "scoop" fails to account for the different weights of coffee beans (their organic makeup and the way they were roasted affect weight) and how awake you are when you arrive in the kitchen.
Knowing the proper weights of coffee and water to measure is about the ratios. (We actually tend to believe much of life is about the ratios, but that's another story.) And, since ideal taste is personal, so are ratios. We recommend starting with around a 17:1 water to coffee ratio and adjust from there. If you're brewing a V60 pour-over, start with 370g water and 22g of coffee. Remember, the point here is to develop consistency and discover the ratio that works for you so you can enjoy every cup you brew.
When you weigh coffee, weigh out the whole beans before running them through the grinder, which leads us to the next maxim: grind size.
Grind it Out
Since the size of grind matters, it's highly advisable to use a burr grinder to make sure you're grinding consistently and evenly. These are available as electric or hand-crank versions. Make the investment; you won't be disappointed.
For single cup pour over, you'll want your grind to be something like, "medium fine" but this is vague. Think beach sand. One of the best ways to know if your grind is in range, is how long your coffee is taking to brew if you're making a pour over. You'll want your single cup pour over brew to take something around 3 minutes. If the grind is too coarse, the water will pass through more quickly and you'll fail to properly extract the coffee; if too fine, it could take 5 minutes or so and you're going to over extract. You'll taste the difference!
But that's for pour over. Grind size is dependent on your brew method and equipment. The science here is the longer your brew method requires the water to be in contact with the coffee, the coarser the grind should be (e.g. French press), and for shorter contact time, you'll need a finer grind (e.g. espresso). An exception here is the unique brewing of Turkish coffee in a classic ibrik that calls for a fantastically fine grind and boiling of the coffee with the water, without any filtering. Yes, indeed. But that digresses somewhat from the general understanding of coffee extraction.
Turn Up the Heat
This is straight forward but often overlooked. Ideal water temp should be 195 - 205 degrees, which is just below the boiling point which, if you remember high school science class, is 212 degrees F. If you have an instant read thermometer, you can monitor this easily and accurately. If you don't have one available, bring your kettle to a boil then move it to a cool burner and let it sit for 30 seconds or so and it should be within range.
Dylan Siemens, winner of the 2017 Brewer's Cup Champion at the Specialty Coffee Association events in Seattle, used three different water temperatures to brew the perfect cup of Green Tip Geisha from La Palma y El Tucan farm from Colombia. Kettle in one hand and instant read thermometer in the other, Dylan took coffee geekness to increasingly new heights. And, in the blind tasting, his brew came out on top, reminding us again that water temperature matters.
It's worth noting that many home automatic drip brewers do not heat water hot enough for proper extraction/brewing. Bonavita and others are now making special drip brewers (with thermal carafes) that remedy this.
In other places on this site, we explore particular brewing methods more deeply, but this information above is the groundwork for brewing optimal coffee. Consistently.
Finishing Touch
We end this overview by returning to where we started: the art of serving. 
We include a couple words here because we believe in the realness and power of presentation. After going through all the painstaking work of selection, roasting, grinding and preparing a perfect cup of coffee, what this coffee gets poured into is important. Really.
We’re not suggesting you narrow in on fine china. Honestly, we believe fine china is usually pretty far down the list. We’re simply making the case that the type of brew, the way it’s been prepared, and the context it’s being enjoyed, should all be considerations when choosing what to serve it in. A crisp, white mug on a checkered table cloth in an outdoor breakfast setting; a cold brew served up in a tall, clear glass with ice and a long spoon for afternoon break; a small, richly colored bowl for a French-style café au lait on a cool morning; and, heck, if you’re camping, serve up that amazing Kenya in an enameled tin cup without shame!
Again, the point here is to simply urge you to not overlook this last step. Your cup, mug, glassware or whatever you serve coffee in—even if it’s only for your personal consumption—matters. Your favorite café probably understands this, why not embrace that at home. Presentation isn’t everything, but it’s that final punctuation that suggests you’ve taken this whole coffee thing quite seriously. And if you weren't legitimately serious, you wouldn't be reading this.
The final reminder is that brewing brilliant coffee is ultimately about creating wonderful experience. Everything above is intended to provide suggestions along with some understanding and science to back them up—but experimentation is often the best source of experience. So experiment. If that means you mess up royally at times, that's probably all the better. And you'll find yourself in good company.
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Glossary