Cold Brew Coffee VS Vietnamese Phin Coffee: While scientists have been extensively studying the hot extraction process, we know that water temperature can affect the acquisition of aromatics, caffeine content, total solid content, and antioxidants. Several studies have compared different heat extraction methods with physiological and sensory properties.
Conversely, little scientific research on cold coffee’s physical and sensory properties has been published despite the increasing intake and interest in the complex coffee market. Therefore, subjectively, we talk about Cold Brew coffee as a new movement instead of its natural benefits. You and I’ll compare Cold Brew coffee and traditional coffee to see if it’s any different!
Cold brew coffee and other extraction methods
Many methods have been born to extract coffee, and most of them use high-temperature water (near boiling point) and short extraction time (no more than 5 minutes). However, in recent years, several new methods have become popular.
Cold-brew, also known as cold blending, refers to the extraction method performed at room temperature (20 to 25°C or more challenging) for more extended periods than the traditional hot extraction method, with a longer duration (usually from 8 to 24 hours).
Low temperatures and prolonged exposure create a coffee-from-coffee drink with different physical and sensory characteristics. These parameters affect the extraction rate and how the flavor compounds present in coffee interact with water.
Since the chemical compounds present in coffee exhibit different chemical properties (e.g., polarization and solubility); therefore, they have different solubility dynamics. In general, higher temperatures increase solubility and affect the slightly saturated pressure of aromatherapy compounds.
“In the research category, the term hot extraction refers to coffee prepared in hot water near boiling temperatures – in other words, this is the traditional way of extracting. And cold extraction or cold extraction refers to cold brew coffee or methods of brewing coffee with water at room temperature (or lower).“
The physiological properties of cold coffee extract
Coffee makers and enthusiasts often suggest that cold brew and hot coffee from coffee have different flavor profiles. This difference stems from the physiological properties of cold coffee.
The size of the beans after grinding is the most significant factor affecting the physiological parameters of cold extract coffee, then the extraction time. Coarse grinding and long extraction times increased extraction yield (EY) and total dissolved solids (TDS) in cold brews. At the same time, both of the above factors, pureness and extraction time, also affect the entire phenolic content (TPC) of cold coffee.
Chlorogenic acid and its related molecules are the primary polyphenols found in coffee, accounting for 7-9% of dry mass (depending on the type of coffee). Overall, polyphenols from coffee are highly bio-biological with powerful antioxidant properties and are beneficial for human health.
Particle size, time, and temperature
People put the coffee grounds into a filter bag and then put it in a water bottle to extract to prolong cold coffee. During extraction, this “packaging” effect may have affected diffusion, reducing the dissolved solid content (TDS) as well as the rate of coffee extraction (EY).
Recent studies have determined that particle size, particle uniformity, and filter shape are the main parameters that impact the permeability and diffusion of solids during cold coffee extraction.
On the other hand, the long extraction period applied in cold extraction tends to increase the values of TDS, EY, and TPC, even when using the raw coffee grinding method. The water temperature can be considered the driving force for extracting chemical compounds found in coffee powder during brewing.
However, the temperature is low during the cold coffee making (lower than room temperature). Therefore, the extraction and diffusion of some compounds require more time to compensate for low temperatures. That may explain why cold brews with longer extraction times represent EY and TDS.
Configure the taste of coffee
In terms of taste characteristics, the results of experimental studies show significant differences in taste, aroma, afterthink, acidity, and richness of hot extracts with all cold extracts. However, the overall effect on the taste of cold extract coffee is not so different from the case of hot quote.
As a result, reviewers showed that although some of the flavor characteristics in cold brew coffee were “weaker” than hot drinks, the taste of the cold brew, according to the overall impact, may be at an acceptable level for coffee drinks.
More specifically, we can summarize some of the flavor characteristics of cold brew as follows:
- The flavor profile of cold coffees is a specialty of malt flavors, which are significant differences from their hot extracts. Other flavor attributes such as almonds, flowers, red fruits, and bitterness are also people rated as having high scores in cold coffee.
- In the scope of the study, cold coffee brewed for 18 hours was the most acceptable to consumers by taste profile. Coffee aged 14 hours showed lower aftertaste properties than samples using hot brewing methods.
- In general, cold coffee can exhibit a higher intensity of sugar caramel, sweetness, and bitterness, which still shows balance with a smooth body.
So, is Cold brew coffee better?
Many factors influence each preparation method, and the more we evaluate quality based on many different aspects. The general comparison of cold brew and traditional coffee will be incredibly lame.
In summary, some physical properties, such as the rate of extraction, total dissolved solids, total phenol, pH, and acidity content, can be strongly affected by particle size and extraction time. Therefore, we need to consider the distribution of particle sizes and extraction methods in their complex relationship with diffusion.
With cold coffee, the long exposure time (22 hours vs. 14h) helps increase the rate of extraction, dissolved solids, total phenol content, and acidity. All cold coffee brewing methods show less acidic and flavor characteristics than hot extracts.
Coffee exists in both scientific and artistic states. We cannot separate the molecular science of a coffee bean from the craftsmanship of a barista placed on it.
Therefore, while some individuals who love hot coffee may turn to delight in the taste of cold brew due to brewing techniques, others, after tasting cold medicine, can find the authentic taste of a specialty coffee that people fully extracted with hot water. After all, coffee has a way of persuading a “believer” in its way, and we call it “gu.”