Cold Brew Coffee Extraction

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This review explores the chemistry of cold brew coffee extraction. Understanding the technical aspects, such as the Specialty Coffee Association’s recommended guidelines for cold-brew extraction parameters, can enhance your cold brew and help refine your recipe.

This picture is from a photoshoot for the website That’s Cold Brew – https://thatscoldbrew.com/. The session focused on taking photos of iced coffee made with cold brew coffee or chilled hot brew coffee. The point of the session was to showcase the iced coffee recipe wher the coffee is frozen into coffee ice cubes and milk or water is poured over the coffee ice cubes.

Here are a few

  • Brewing coffee, whether cold or hot, involves dissolving the soluble compounds in coffee grounds to flavor and caffeinate our brew.
  • There are several ways to enhance the dissolution of soluble solids in coffee grounds. The most common method is heating the solution.
  • Heating is not the only way to increase extraction. You can also adjust the grind size and agitate the solution.
  • With cold brew, we need to wait longer for complete dissolution because there isn’t enough heat to accelerate it.

Important Tips About Cold Brew and Extraction

Every coffee brewing method is unique. The French press, an immersion method James Hoffmann describes as forgiving and full-bodied, is preferred by some, while others prefer espresso. Others enjoy paper-filtered coffee made with light-roasted beans.

Regardless of what led you to cold brew, there’s a 50% chance you prefer a stronger cup. According to the Specialty Coffee Association’s guidelines on cold-brew extraction parameters, most cold brew recipes emphasize caffeine extraction over coffee flavor. As a result, cold brew can become a wasteful preparation method, which is quite costly.

To achieve a strong, flavorful coffee, consider deviating from popular cold brew recipes that typically use extra-coarse grind sizes and steep for up to 12 hours, as recommended by the Specialty Coffee Association (SCA). While this method extracts most of the caffeine, many other soluble solids remain undissolved, resulting in a light beverage. If you enjoy this style, continue with it. However, if you prefer a stronger cup without the bitterness of hot brew, read on.

If you are familiar with brewing coffee, the concepts discussed here will be easier to grasp. We explain these concepts as we go, but we avoid excessive detail to maintain conciseness.

Brew Time

Coffee extraction is often misunderstood. When hot water and ground coffee are combined, they must remain in contact for a specific duration. Prolonged contact can lead to the extraction of bitter compounds, while insufficient steeping results in a weak brew. According to the SCA, the optimal contact time varies depending on the brewing method.

Grind Size

The grind size significantly impacts extraction yield. A finer grind enhances extraction efficiency but requires a shorter contact time between the grounds and water. This relationship between grind size and brewing time is crucial for achieving the desired flavor profile. The SCA recommends adjusting grind size based on the brewing method to optimize extraction.

Brew Temperature

At high temperatures, coffee compounds dissolve faster. Low temperatures dissolve bitter compounds in negligible amounts, but high temperatures dissolve them more quickly. Because of this, the SCAA has a standard for filter coffee brewing. When brewing hot coffee, we must be very careful with the grind size and the brewing time. The high brew temperatures can dissolve undesirable compounds very rapidly.

Cold Brew Coffee and Brewing Parameters