When it comes to enjoying the perfect cup of coffee, there are many factors and variables involved that affect coffee, from how it is handled at origin to how it is prepared for brewing. Some of those variables include the variety of green coffee, roasting method, time from roast to brew, grind size, water quality, water temperature, and so much more. Ultimately, brewing methods and techniques depend on the preferences of the brewer, but there are suggested guidelines used by coffee professionals everywhere, which allow them to achieve a consistently good cup of coffee each and every time. Those suggested guidelines center around five primary variables controlled by the brewer. They include the: 1) Amount of ground coffee or dose 2) Grind size 3) Water temperature 4) Time allotted for brewing and 5) Amount of brewed coffee or yield. In this month’s blog, we’ll be exploring variable number two, Grind Size.
Figure 1 – Photo credit: Coffee Channel
Understanding Grind Size
When considering coffee grind, there’s a coarseness to fineness continuum, as noted in Figure 1 above. Recommended grind size is based on the desired brewing method, which is determined in part by the amount of time coffee is in contact with water during the brewing process. A coarser grind is generally prepared for longer contact time with water. The finer the grind, the shorter the contact time. To dig in a little further, finely-ground coffee has a greater surface area than coarsely-ground coffee, therefore more of the coffee comes into contact with water allowing water-soluble particles to be extracted much more quickly. In comparing brewing methods, the French Press typically utilizes a coarse grind similar to that of sea salt (see Figure 3) with about four minutes of water contact time. Espresso lands on the other end of the spectrum with a fine grind similar to very fine salt and a water contact time of around 30 seconds. Another way to look at the difference between these brew methods is immersion-style brewing vs. pass-through brewing. In immersion brewing, such as the French Press brew method, water and grinds come into contact and remain together for the entire duration of the brew. With espresso and other finer grind brew methods, water contact time is very short as water continuously passes through the grind.
Preparing Your Grind
Grind Right Before You Brew – When coffee beans are ground in preparation for brewing, the unique aroma of that coffee is released. The grinding process allows oxygen in the air to pull oils from the freshly ground beans. It is these oils and aromatics that could and should be in your cup. The ground coffee will continue to oxidize. Over the course of hours, freshness declines and within days, ground coffee will start to taste stale. With this in mind, we suggest brewing within minutes of grinding, if possible.
Figure 2 – Image credit: Home Grounds
Selecting the Right Type of Grinder – Another consideration in this process is the tool or machine used for grinding. There are a number of options available in the market for the home-brewer, although there is a significant distinction between two common varieties – blade grinders and burr grinders (see Figure 2). Although blade grinders are typically more affordable, they are not usually recommended. The blades are rough on coffee beans and create an inconsistent grind size with both coarse and fine grounds in the same batch. In contrast, a burr grinder grinds beans between two abrasive surfaces called “burrs.” Those burrs are set a certain distance apart based upon the grinder’s settings, which dictate the size of the grind. Although typically a bit more expensive than a blade grinder, burr grinders are known for their precision and ability to produce consistently-sized grinds every time. Manual burr grinders can be found for less than $50 with automatic burr grinders starting around $100. At Commonplace Coffee, we both endorse and sell the Baratza Encore grinder for its consistency, ease of use, and affordability.
Understanding grinding basics is a powerful tool. Adjusting grind size and discovering the effect it has on your brewing method can be both exciting and challenging. Ultimately, creating the perfect cup of coffee at home depends on the palate of the home brewer and their preferred brewing method. The chart below (Figure 3) shows the continuum of grind sizes with associated brewing methods. It serves as a great jumping off point for anyone looking to get started. Familiarizing yourself with your specific grinder settings is also crucial to achieving the appropriate grind size and texture best suited for your brew method. Most at-home grinders include a guide to get you started such as this handy multi-product guide offered by Baratza.
Figure 3 – Image Credit: Honest Coffee Guide
So, what’s our owner’s go-to brew method and grind setting? Although it has undoubtedly shifted at times over the years, TJ always finds himself going back to the AeroPress with a medium/fine grind setting. He loves its versatility, finding it great for home and travel. It also produces an excellent cup of coffee. In fact, a favorite Commonplace story is that up until their most recent redesign, AeroPress’s packaging prominently featured a quote of TJ’s for more than a decade, which stated, “The best cup of coffee of I’ve ever had.” Although we might still be bitter about its removal, it’s definitely a method worth trying if you haven’t yet!
Have thoughts, questions or comments about any of this or just want to learn more? Leave a comment below or check out our Coffee & Brewing classes!