Standards of the Cold-Brew Process
From the farm to your cup, a variety of factors affect the quality, taste and environmental impact of the coffee you drink. If you’re searching for the highest-quality, best tasting, and most sustainable cold-brew coffee products, learning about the cold-brew process will help inform your decision. Here’s what you should know before you buy:
It starts here. What kind of coffee beans, as well as where and how they are grown and processed affect not just your enjoyment, but the impact of coffee cultivation on the environment.
It’s pretty obvious that without coffee farmers, there would be no coffee. So it stands to reason that ensuring the safety and financial security of the farmer is not only the smart thing to do, it’s the right thing to do. Accordingly, commercial coffee bean purchasers in the cold-brew sector should follow voluntary guidelines that mandate fair, livable wages for coffee growers and laborers. Similarly, standards that ensure workplace safety in coffee cultivation are a must.
How the coffee is grown makes a big difference, too. Consider seeking out cold-brew coffee products made with shade grown coffee. This growing technique not only results in better beans, it helps preserve the rainforests and wildlife where they are grown. This increased biodiversity promotes healthier soil and helps reduce the need for water.
Shade growing also promotes natural insect and pest control. That’s important, because cold-brew standards dictate the use of non-GMO, organically grown coffee raised without toxic pesticides, reducing potential risks for growers, laborers and consumers alike.
How can you, the consumer, know if the cold-brew coffee products you buy are produced under these conditions? ? One shortcut is to look for products made with Fair Trade coffee. That ensures that the coffee was grown sustainably and that the grower received a fair price for their beans.
What matters here is the species of beans and how they are processed before roasting.
The two main species of coffee beans are arabica and robusta. Without exception, the finest cold-brew coffee products will use 100% arabica beans. Though coffea arabica is more difficult to grow and its plants produce lower yields, the more delicate and nuanced flavor profiles and lower acidity of arabica beans yield a vastly superior final product.
After harvest, there are two main ways of processing coffee beans before they are roasted.
In dry-processing, also known as the natural method, the fruit of the coffee plant, called the cherry, is dried whole. Then the exterior layers of the fruit are milled away. What’s left is what we coffee drinkers recognize as the coffee bean. Dry-processing leaves coffees with a distinct, winey flavor. It is not well suited for coffees grown where rain is abundant. Since coffees grown in more dry, arid conditions tend not to produce the best tasting cold-brew products, knowing that a product underwent dry processing is a clue that it doesn’t meet strict cold-brew standards.
In wet-processing, often called wash processing, coffee cherries are soaked in water, loosening the pulpy layers of the fruit that surround the beans, which are then removed before the beans are dried. Wash processing is less likely to introduce unintended, intense and/or unpleasant flavors in the coffee. Rather, coffees made with washed beans tend have brighter yet milder flavors. While other factors may play a more important role in your enjoyment of the final product, to meet the highest cold-brew standards, wash processing is definitely preferable.
Aside from choosing the highest quality organic shade-grown coffee beans to start with, the method and craftsmanship of the coffee roasting process may have the biggest impact on your cold-brew coffee enjoyment.
It is estimated that 99% of all coffee is roasted using a drum roaster. If you’ve ever been near a coffee roasting facility and were nearly knocked over by an intense, almost acrid coffee aroma, it’s a good bet they are using a drum roaster. Drum roasting can accommodate large batches of coffee beans, so it is the cheaper and faster method. But it directly transfers heat to the beans, which can leave a bitter, or burnt taste. Drum roasting also tends to heat unevenly, so parts of the same bean may be over roasted and under roasted simultaneously. That’s not a recipe for the most satisfying cold-brew coffee.
True aficionados, on the other hand, know to seek out coffee that has been air roasted. Air roasting equipment is expensive and can only be used to process small batches of beans at a time. Those are two of the main reasons why only 1% of all coffee in the world is roasted this way. Another reason is that air roasting requires a much higher degree of craftsmanship from the roaster. In air roasting, the temperature is constantly modulated to avoid any burned beans. And where drum roasting is more like using a blunt instrument, air roasting requires more skill and finesse. Indeed, the precise control it gives the roaster virtually demands that they customize the roast of each small batch based on the specific beans to be used. No wonder, then, that the cold-brew standards favor air roasting.
Many might assume that a finer grind makes a finer drink. In fact, the opposite is true for cold-brew coffee. For the smoothest end product, you want to look for a coarse grind that leaves slightly larger coffee particles.
The level of dissolved minerals in the water used to make cold-brew coffee plays a critical role in its smoothness The pH of certain types of mineralized water, such as water naturally cured in the limestone aquifers of the Texas Hill Country, is considered ideal for getting the smoothest, most flavorful results.
How much coffee should be used? While extracting less of the stuff you don’t want from the bean—overwhelming, “off” flavors and excess acidity—cold-brewing also extracts less caffeine than hot-brewing. But many, if not most, cold-brew drinkers want and expect cold-brew to pack a strong caffeine punch. To achieve this, producers have to use much more ground coffee per unit of water. A water to coffee ratio of 4:1 (80% water/20% coffee), while more costly to make, results in a highly caffeinated cold-brew that is smooth and easier on the stomach.
When it’s time to steep the cold-brew coffee, room temperature water yields a bigger and better flavor with lower acidity. But it does so slowly. Consider 12 hours of steeping time the minimum, and 16 hours the preferred standard. And to ensure that the cold-brew has achieved the right combination of high caffeine and smoothness of flavor, brewers aiming for the highest standards keep the grounds constantly agitated—no sleeping during steeping.
Photo: Robin Corps
Great cold-brew coffee will have a smoothness that’s unlike any traditionally brewed coffee. If someone tells you bitter means better, they are fooling themselves. Done properly, cold-brewing maximizes smoothness and minimizes bitterness.
You will likely find that coffee meeting the highest cold-brew standards is easier on your stomach, and is less prone to stain your teeth. That’s because it has a lower acidity. What makes for smoother flavor also makes for a drink with lower levels of harsh acidic tannins and oils. For these reasons, strict adherence to the proper cold-brew process is highly important.
Because master cold-brewers can reduce the amount of undesirable coffee characteristics (acidity, off notes, dull flavor), they can increase what many coffee drinkers want more of: caffeine. Imagine coffee drinks that deliver higher caffeine content, bigger flavor and ultra-smoothness, yet with less acid. Those are coffee drinks made to the highest cold-brew standards.