Espresso Brew Ratio

The Coffee Brew Ratio

Many articles are available that cover the coffee brew ratio. It has become generally accepted in the specialty coffee industry that the 2:1 ratio is best. For the most part we have found this to be true. Over the years, the majority of our espresso recipes have been within this range plus or minus ten or twenty percent. However, with the introduction of pressure profiling we have begun to reexamine this idea. 

Breaking the Rules

The lack of flexibility can be difficult to deal with in the specialty coffee industry. Many times the trends that become standard "rules" can be traps that limit our experimentation and creativity. While there are often good reasons for these rules, it is important to understand why they exist. When we fully understand why they exist, we can develop ways to manipulate those boundaries to our advantage.

In the last few years as a coffee professional, I have witnessed some common terms come and go. Chatter in cafes about their ristretto, or double ristretto shots were almost a badge of honor. If your cafe wasn't brewing single-origin micro-lot expresso shots, than you certainly weren't Third Wave. While trends come and go, some of these rules have stayed with us.

Many of the advancements we can point to today are a direct result of exploration and experimentation. The abundance of hyper-accurate digital scales in cafes across the globe are one such achievement. The scale is an incredible tool that has removed barriers in communication for coffee professionals world wide. Suddenly we were able to speak a common language using a  quantifiable measurement. Baristas could discuss their espresso recipe using grams in and grams out. This description combined with a simple timer formed the basis for modern espresso discussion.

As we progressed, the conversation began to revolve around extraction percentages. Coffee researchers reprogrammed modern laboratory tools to measure solubles in water, leading to the first discussions on coffee extraction percentages. As we become more and more precise in our descriptions of coffee brewing, our understanding of the science becomes more clear.

A Coffee Brew Ratio

You may often hear one common question with regard to coffee extraction. "What is your recipe?" The answer will typically involve a slew of numbers to describe the dry coffee weight, the amount of brew water by weight, and the amount of time the two are in contact. While this is all pertinent information, it only tells part of the story.

The current understanding among many in the coffee community is that a standard brew ratio for espresso should be 2:1. If brewing a 20 gram dose, most will end the brew near a 40 gram yield. This ratio has held true in our experience to this point. Brewing with a more coarse grind can help to push this ratio further, but often the perception of the coffee's body would become thinner and watery. It is still possible to serve excellent espresso in this manner, but it would often have a difficult time standing out in milk based drinks.

The 2:1 ratio has become somewhat of a compromise between the true boundaries of extraction, and a balanced latte. Short of having two separate machines to brew espresso, options were limited. Finding excellent espresso is still possible using the 2:1 ratio, but it seems that we were leaving a lot on the table.

Pressure, and the Coffee Brew Ratio

In order to understand the effects of pressure on our coffee flavor, we had to taste a lot of coffee prepared in a lot of different ways. Until now, we have not felt comfortable making any observations of our experiences. In fact, only recently do we feel that we have a more thorough understanding of our changing parameters in relation to brewing pressure. Please understand that these are still preliminary observations. Our understanding of brewing with variable pressure will hopefully grow with experience, and that will likely change our opinions on the subject.

The Approach

We began immediately playing with different pressure profiles to see how the espresso would change from our standard brew recipe. The most obvious changes dealt with the perception of acidity, body and sweetness. After several months and many different coffees, some common patterns began to emerge. After many repetitions, it became easier to predict the outcome that certain changes to the pressure profile would produce. By adjusting the pressure profile, we could mold the coffee to meet our expectations. This would open up a world of possibility.

It was reasonable to believe that coffee brew ratio of 2:1 may no longer apply. We could now push that further, and with a few adjustments create our own ideal ratio. One common observation we noticed occurred when we dropped the pressure towards the end of the brew cycle. The body of the coffee would stay in tact, but the shots would still taste sour. This would allow us to extend the brew ratio by over 25 percent in some cases, while keeping the body balanced. In fact, the combination of stretching the brew ratio and lowering the pressure towards the end enhanced the sweetness without introducing tannins.

The Results

This revelation gave us a new tool. With the proper pressure profile we could now hit all three of our marks while increasing extraction percentage. Ideal peak pressure and appropriate drop allowed for optimal acid quantity and flavor quality. Surfing below the Sweetness Curve prevents over extraction of tannins. Finally, proper ending pressure helped to further the coffee brew ratio and retain sweetness.

If you read this far with the expectation of getting a new brew ratio to blindly follow, apologies. The goal from the onset of these articles is to question our understanding of coffee brewing. The only conclusion we have reached at this point is that perhaps it is time to uncouple ourselves from our current guidelines and see what changes can have a positive impact on our brewing abilities.

After creating a separate pressure profile for each of our tested espresso offerings, we discovered that each one has a completely different ideal coffee brew ratio. Small adjustments with pressure curves created drastic but predictable results. We can create a design for ideal coffee brewing parameters with a more firm understanding of these variables, . The more we use these variables to our advantage, the less confined we are by industry standard rules.