Cold brew preparation from an expert perspective

Acidity in cold brew

The reason why many people like cold brew is its lower acidity, which is confirmed by tests. However, it should also be taken into account that roasting also has an effect on the lower acidity. This is because the total titratable acidity decreases as the roasting level increases.

The choice of the correct roast may therefore be more important than the preparation method. If you stick with a single bean, the brew method can help you achieve the desired acidity or non-acidity.

Now back to the research. At first glance, the differences found in pH in research may seem minimal, but in reality, changes in values even in the order of tenths are noticeable.

Thelowest pH values (i.e. higher acidity) for both Nariño (4.81 pH) and Huila (4.88 pH) were observed withcoarse grinding and 14 hours of extraction. As you are well aware, even in the case of hot coffee, a shorter extraction usually leads to higher acidity.

Moreover, the amount of pH depends on the country of origin, the maturity of the coffee, the processing and the whole coffee handling process. This is also shown by research which shows that these particular coffees tested are more acidic than coffees from different parts of the world on average. In fact, when comparing the pH of coffees from different countries, the values range between 4.96 and 5.14 pH.

Hot vs. cold coffee

You've no doubt had the experience of making coffee but not being able to drink it in time. In that case, you must have found that your coffee tastes different. Its flavour profile has changed, the fruit has become more pronounced or, on the other hand, the flowers have become more prominent. This is also true if you prepare the coffee cold straight away.

The same ratio of coffee to water was used in both cases during the test. So what were the results? Both cold-brewed coffees showed higher values in the extraction yield and total dissolved solids categories than their hot counterparts, especially when using a coarse grind and a long extraction time (22 hours).

Thedifferences in gallic acid values can be explained by the presence of several water-soluble polyphenolsin roasted coffee , which exhibit different chemical properties, some of which, such as chlorogenic acids, caffeine and soluble melanoidins, are removed at different contact times.

Flavour profile of cold brew coffee

In this study, the taste profile of coffee beverage was evaluated in terms of general characteristics such as aroma and flavor, acidity, body, taste and aftertaste.

Overall , thecoffees prepared with hot water were more pronounced in both aroma, body or taste. This is no doubt also due to the water/coffee ratio used, which was 1:10. However, it is more common to use a ratio of 1:16 for hot coffee, while for cold brew a ratio of 1:10 is appropriate.

The values for all categories were fairly even, but the overall best impression was made by the two coarsely ground coffees with an extraction time of 14 hours.

For the coffee, individual flavours such asdifferent fruits, nuts, spices and other aromatic foodswere also evaluated as part of the flavour profile. Cold-brewed coffees had higher scores for malt, pepper, almond, cocoa and forest fruits than hot coffee.

Overall, then, it was found that cold brew can exhibit higher levels of caramelisation of sugar, sweetness and bitterness. The body of the cold brew samples were creamier and creamier, while the hot coffees were rated as more sour and pronounced in terms of flavours as well.