The Science of Cold Brew and Why Taps Deliver the Best Flavor

Hello coffee lovers and science geeks. Ever wonder why cold brew coffee on tap has such a delightful taste?

The secret lies in the brewing process. Let us guide you through the steps by learning about the various factors that contribute to brewing coffee and exploring the science behind the process. When we delve into the chemistry of cold brewing, we understand why this method produces such a refreshing and richly flavored coffee.

Cold brew coffee is made through a slow extraction process, where coarsely ground coffee beans are soaked in water for several hours, typically ranging from 8 to 24 hours. This method highlights distinctive characteristics that differ from those of hot-brewed coffee.

There are certain factors in making cold brew coffee to achieve a nice, refreshing cup, including:

• time of brewing
• temperature of the water
• the amount of grounds
• grind size

Understanding the cold brewing process

Coffee is steeped in water for between 8 and 24 hours, allowing the water to fully saturate the beans. When making old brew coffee, baristas recommend using coarse grounds instead of fine ones, even though they have a better extraction potential. While a smaller grind size leads to greater solubility, there are a few reasons why coarse grounds are preferred for cold brewing:

• Fine coffee bits can get through the filter, ending up in your mouth, and that's not a pleasant feeling.
• Insoluble coffee particles can cause the cold brew to lose its freshness more quickly.
• The tiny particles often clog the pores of the filter used for brewing.

When it comes to cold brewing, the water temperature plays a crucial role in the extraction process, as the solubility of coffee compounds depends on the temperature. While hot water rapidly extracts a wide range of solubles (typically in minutes), cold water extraction limits the solubility of many compounds, resulting in a slower process (in hours) and greater selectivity.

While the overall caffeine concentration varies based on the coffee-to-water ratio, cold-brewed coffee typically contains more caffeine per ounce than hot-brewed coffee, primarily due to the extended extraction time (8-24 hours).

Cold brew coffee is generally less acidic because the extended maceration in cold water minimizes the extraction of acidic compounds, which are highly soluble in high-temperature water but less so in cold water. The result is a less acidic coffee with a naturally sweeter taste and smooth texture that is easier on the stomach.

Cold water extracts fewer oils from coffee beans, which gives hot-brewed coffee a more bitter taste, resulting in a cleaner flavor. The extended cold brewing retains more aromatic compounds that are lost in hot brewing due to high temperatures.

The role of nitrogen in enhancing the aroma

Nitro coffee is cold-brewed coffee infused with nitrogen gas. It is typically served from a can or on tap. The nitrogen bubbles give a foamy head, a creamy texture, and preserve the coffee's natural flavors. Nitrogen gas forms much smaller and more numerous bubbles than carbon dioxide (CO2), which softens the harshness of roasted flavors and creates a creamy mouthfeel.

This odorless gas displaces oxygen, preventing oxidation and preserving the cold brew's flavor for a more extended period. By reducing the coffee's bitterness, nitrogen makes the coffee taste naturally sweeter without the need for added cream, sweeteners, or sugar.

Try cold brew on tap for the best experience