Coffee Brewing Overview

December 12, 2015 Uncategorized

If you’ve met me before, you’ll know that I think that there’s something real special about manual brewing methods; give me a Chemex or siphon over a Technivorm or Bonavita any day. This isn’t putting down any of these brewers at all, they do an incredible job, rather I’m saying that there’s a je ne sais pas about brewing your coffee by hand (a lot like the satisfaction you get building a bookshelf or table rather than simply buying one).

That all said, anyone with a pointer finger and the slightest, sleepiest attention to detail could brew a great cup with a Technivorm. To brew a “perfect” cup on a manual brewer, you need to make some bad coffees first, or at least have a good understanding of what makes good flavors show up and what contributes to the appearance of bad ones.

As I stated in my much longer-winded blog posts previous, the basic elements that contribute to what you get out of your cup (both in manual and push-button brew methods) are: water, flow-rate, grind, proportion, and freshness.

Here’s a quick overview of these elements and how they affect your brew:

Water: Water makes up the majority of what you’re drinking (I’ve read various reports stating anywhere from 92%-97% of your final brew), so if your water tastes bad, so will your coffee. Taking water a step further, the temperature with which you brew is also vitally important to what your cup will taste like. The hotter your water, the faster its molecules work; the faster they work, the quicker the solubles in your ground coffee will be extracted. The cooler your water, the slower the molecules work, etc.

Flow-rate: Continuing where “water” left off, there is a perfect amount of contact time between your water and your ground coffee before you stop extracting delicious flavors and start on the nasty stuff. This is true both for direct-contact methods (French press) as well as pour through (v60) or drip methods (technivorm). Ever notice a French press tasting delicious with your first cup, then the second being bitter, the third even more so? That’s because despite pushing the grounds down the brew is not adequately separated from the ground coffee. So, even though you’ve pushed the grounds down, the mesh barrier is not sufficient to stop extraction (i.e. an extended amount of contact time). The result is the nasty stuff coming on through from the grounds and on into your brew.

This same effect occurs when your pour over or drip coffee takes too long to pass through your bed of grounds; the passing water pools and thus over extracts (remains in contact for too long with) your coffee. The opposite affliction can also occur if your water passes through the bed too quickly (only extracts sour/grassy flavors).

Grind (drip, pour through methods): Your grind has a direct influence on flow-rate and thus has great pull in the ultimate extraction of your coffee. The finer you grind your coffee, the slower your water will pass through the bed of grounds, and the more extraction that will occur. Conversely, the coarser you grind your coffee, the quicker the water will pass through your bed, and the less extraction that will occur.  Think of it this way, if you replaced coffee beans with rocks, would the water pass through pebbles quicker or sand quicker?

Grind (general overview): While the previous section is pertinent information mostly for pour-through methods, grind also has a direct relation to extraction for all brewing methods. As you grind you coffee finer, you are exposing more surface area to the water and thus allowing for a quicker extraction period (shorter contact time). The opposite is also true, as you leave more surface area covered; you are creating an environment where full extraction will take longer. To illustrate that point, think of a coffee bean as the 48 contiguous states and the surrounding ocean as the brewing water trying to extract the flavors. It would be very difficult for the brew water (or ocean) to get to the middle of the bean (i.e. Kansas) as things currently are. Now if you grind the bean (or break up the states) and place them in that same water as broken bits, the water would now have easy access to Kansas without having to completely saturate the outer sections of the country to get to it. Taking that one step further, imagine the flavor payload is actually in Topeka. Now if you grind finer and separate the states by cities, the water now has quicker access to even more of the coffee’s payload.

In short, the level of fineness will directly impact (along with water temperature) the speed of extraction simply by allowing more access to the inner parts of the bean as well as the outer. It is important to realize, however, that coffee has a finite number of pleasantly aromatic solubles before the water begins to extract the nasty stuff. So, if you let ground coffee remain in contact with the water for too long or too short (at a certain grind fineness and a certain water temperature) you will begin to extract bitter flavors (too fine, too long) or only extract the sour and acidic flavors (too coarse, too short).

Proportion: Proportion is the pillar with which all the aforementioned values stand. It is, simply stated, the amount (or proportion) of coffee to water. You can have the correct water temperature, grind, and contact time but if your proportion is off, then you will ultimately end up either under- or over- extracting your coffee simply because you have too much or too little water. It is here that I will highly recommend using a scale to ensure your proportion remains consistent. I personally think that the 15:1 (water to coffee) is ideal for optimum extraction.

Freshness: If proportion is the pillar with which coffee brewing stands, then freshness is the foundation. Without fresh coffee, none of the previously stated is possible. A coffee bean (or seed) is a cellulose matrix structure (think honeycomb) filled with volatile flavor oils that are extremely susceptible to oxidation. As time passes and the coffee becomes less fresh these oils and flavor compounds oxidize and become rancid. Moreover, the CO2 captured within the structure escapes and leaves the coffee even more susceptible to the elements. In short, old, oxidized coffee is bad coffee.

All the previous was written in the attempt to briefly describe how to make good coffee and to explain, in short verse, why your coffee may have tasted bad in the past. This blog will be followed by brew guides for individual brewing apparatuses including v60, aeropress, chemex, and specific push-button brewers. If you have any questions please do not hesitate to shoot an email to coffee@hartcoffee.com or stop by the roastery at 3404 NE 55th St. Seattle, WA 98105.

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