In the last post we introduced the Coffee Brewing Control Chart; a tool developed in the 60s-70s that is the foundation of brewing good, tasty, coffee. The Chart relates TDS (Y axis) to Extraction (X axis) and brew ratio (diagonals).
Brewing a great cup of coffee is all about dissolving stuff. Not just any stuff, but the right stuff in the right amounts. How things dissolve depends on the solvent, temperature, pressure, and what you are dissolving. Pretend we are in science class doing an experiment. In experiments we like to control variables, so lets use water as the solvent, keep the temperature the constant, and use coffee for what we want to dissolve (Ok, the coffee won't really dissolve, but the chemicals in it will). Coffee has hundreds of chemicals in it. Some taste awesome. Coincidentally, the awesome ones are relatively soluble and easy to dissolve. But there are some chemicals that taste awful; bitter, burnt, chemically, tarry. Luckily, these are less soluble and harder to dissolve. We want to dissolve only the good stuff.
Back to the experiment. The only variable we are going to play with is the coffee. If you put a bunch of coffee beans in water, not much happens. In order to start dissolving the good stuff out of coffee, we need to grind it. The finer we grind the coffee, the more easily stuff dissolves. On the control chart, the finer we grind, the stronger our coffee gets (up the chart). BUT, the finer we grind also can make us move to the right towards bitter; those hard to dissolve awful things start to dissolve if we are not careful. We want to control our experiment so we balance strength and flavour, ending up in the gold box.
When we make coffee at home, we need to control the variables too. So we use the same water each day, heated to the same temp, plus good coffee and the same brewing ratio (1:17). We use our grinder to control strength and flavour, trying to get in the gold box. Pick a grind and brew. If it is too weak or sour, grind finer. Too bitter, grind a bit coarser. BTW you taste sourness on the sides of the tongue and bitter on the back/top of the tongue.
To control the grind we need a good grinder, and by good I mean a burr grinder. Burr grinders produce an uniform particle size which gives us better control over what we dissolve. Many shops sell inexpensive "blade" grinders...fast spinning blades that shred or chop the beans. If you have ever used one you know they create everything from fine powdered coffee to big chunks of coffee. When you try to brew with this, the nasty tasting chemicals easily dissolve from the fine dust overwhelming the good stuff. The coffee is often silty and bitter.
A good burr grinder is an investment, but it will pay for itself in great coffee and it will out last a blade grinder. Check out our newest hand grinder by Handground. I found this at the Global Coffee Expo in Seattle a couple weeks ago. It's an affordable, easy to use alternative to an electric grinder and great for grinding larger quantities of coffee than the slim grinder.