What Science Tells Us About Making the Best Tasting Cold Brew Coffee


To win over consumers, optimize the components most critical to taste

KerryDigest Fast Facts:

  • Cold brew sales in North American are predicted to top $1.4B in 2018.
  • Taste is the main driver for consumers who drink cold brew.
  • Cold brew taste is influenced by bean type, roast level, grind size and brewing conditions.
  • Kerry sensory scientists, chemists and baristas have unlocked the formula for making the best tasting cold brew.

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KerryDigest Full Scoop:

There’s a reason cold brew coffee has the market buzzing: Our sensory research shows that consumers really can taste the difference, and they like it. In fact, nearly 50% of consumers said taste was their primary reason for drinking cold brew coffee—above even the need to satisfy their coffee cravings, according to our recent sensory report, “Just Brew It: Unlock the Secret to a Great-Tasting Cold Brew.”

This trend is here to stay: In fact, the data we've collected suggests cold brew coffee will surpass $1.4B in sales in North America in 2018.

There are still plenty of opportunities to break into the cold brew market. To get the best tasting cup of cold brew coffee, our resident sensory experts, food scientists and baristas worked together to establish four critical criteria for our cold brew. Consider these recommendations for coffee bean type, roasting method, grind size, steep time and temperature as you work on your next cold brew product.

Cold Brew Criteria 1: Coffee Bean Selection
You can make some generalizations about coffee beans. For example, African coffee beans typically highlight more exotic notes such as blueberry or citrus while Brazilian beans tend to be more nutty and earthy with cocoa tonalities.

But it’s difficult to say with certainty that a bean will have certain specific properties. “Differences in soil characteristics; growing elevation; humidity and temperature can affect which taste attributes come through. These and more can affect the levels of moisture, sugars, amino acid quality and quantity and the amount of chlorogenic acids in the green bean,” says Abhinandya Datta, PhD, a Kerry analytical scientist specializing in coffee and tea extracts, ultimately impacting the final flavor profile.

Even the processing steps adopted—such as natural (beans are left wholly in the coffee cherry), semi-washed or washed from the cherry before the drying step—can impact the flavor by modulating the chemical compounds mentioned above. Adding to the confusion, there can even be variation between neighboring farms producing the “same” varietal.

Through our work, we’ve found we can draw out the best flavor by using a signature blend of high quality beans when creating our cold brew concentrates and extracts, each of which contribute one or a few of these desired attributes to the whole blend of coffee.

The takeaway: All beans can be used for cold brew, so consider the desired flavors and end use application when making your bean selection and be open to brewing a blend to achieve the best product.

Cold Brew Criteria 2: Roast Level
Roast level also impacts the taste profile of cold brew coffee. The process of applying heat to raw green coffee beans causes chemical reactions and changes to the beans’ structure. “One of the major reactions occurring in the bean is the Maillard reaction,” says Datta. “This leads to the generation of a plethora of flavor compounds including compounds containing sulfur, aldehydes, furans, pyrazines, pyrroles and pyridines, which are notable for giving coffee its characteristic nutty, malty and caramelized flavor.”

Roasting beans for the longer times and to the hotter temperatures needed to create a darker roast can make the beans caramelize, enhancing the sweet, brown, roasted notes that are staples in coffee profiles. Dark roasts, in particular, tend to be characterized by smoky aroma due to the generation of guaicols and related compounds arising from chlorogenic acid breakdown, says Datta. Just be careful not to take the caramelization process too far; burnt, ashy notes could start to develop and mask the natural and delicate flavor attributes of the beans.

Roasting for shorter times and to lower temperatures can help can help highlight brighter acidity and more delicate nuances, such as fruit or herbal notes. However, if you roast too lightly, flavor profiles will be underdeveloped in the beans, highlighting grassy notes and too-high acidity. Our sensory-analytical study found that cold brew samples that were high on astringency and acidity were disliked more by consumers. “The astringency correlated strongly with higher chlorogenic acids whereas the acidity correlated to citric, acetic and quinic acid, indicating the analytical parameters responsible for the sensory characteristics,” says Datta.

The takeaway: Finding the right roasting time and temperature is often an ongoing experiment, but the goal is to find a place where beans are nutty but sweet without too much acidity or astringency.

Cold Brew Criteria 3: Grind Size and Water Volume
Grind size is important for a balanced extraction during the cold brew process. If the grounds are too large, the coffee will be under-extracted, as there won’t be enough surface area in contact with the water. This could result in a very light, weaker cup of cold brew. If the grounds are too small, the coffee could pull too much bitterness in a dark roast, or make the coffee too acidic.

For cold brew coffee, we’ve found it’s best to use a larger, coarser grind and a greater amount of grounds. This produces a higher coffee-to-water ratio and a smoother, stronger taste profile. In our tests, using a finer grind size consistently led to over-extraction of woody, bitter base compounds.

An increased volume of coffee grounds is key to ensuring you extract enough of the good stuff during cold brewing—the intricate, nuanced sweet, caramelized and fruity notes—without producing woodiness or bitter, ashy and burnt base notes. Having a higher coffee to water ratio with coarsely ground coffee also ensures you have enough total solids so the coffee doesn’t taste watery.

The takeaway: A good rule of thumb for cold brew is to use a coarse grind and to increase your coffee:water ratio by using more grounds than usual

Cold Brew Criteria 4: Brewing Conditions
he general consensus is that traditional hot brew is optimized at a brewing temperature of 190F to 205F. In cold brew, there is no standard range of extraction temperature although, as the name implies, it’s typically cooler than traditional hot brew.

Generally, with any extraction method, the same principles apply: too long a brew time and too hot a temperature can result in over-extraction. Too short a time and too low a temperature can result in under-extraction and a weaker cup that doesn’t pull the full profile.

The takeaway: To craft cold brew products that deliver on consumer preferences for lower bitterness and higher nutty and cocoa notes, the water temperature used should be lower than in traditional brewing, and coffee grounds should be steeped until the desired taste profile is met.

From Asia to North America, cold brew coffee is shifting from an artisan, gourmet beverage to a mainstream staple. To learn more about what consumers prefer in cold brew, we conducted new research, which we compiled in the report, “Just Brew It: Unlock the Secret to a Great-Tasting Cold Brew.” To partner with our cold brew experts, or learn more about our research or products, contact Kerry.

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