There is a lot of misinformation about clarifying juices all over the internet. There are countless news articles heralding a new discovery among bartenders like the use of curdled milk (casein is a positively charged fining agent), while others herald agar agar (another positively charged fining agent) as the newest and best way to clarify a liquid. However, rarely do these bartenders mention the science behind it and just tell you to use that ingredient like its some new sensationalist discovery
. While there may be other ways, below is a primer of the three primary ways juices are clarified in a real world scenario.
Using a Centrifuge
The first is to put the liquid through a centrifuge. A centrifuge spins a liquid incredibly quickly and will separate the mass of the liquid by its specific gravity.
However, most people can’t afford a centrifuge, it can greatly affect taste due to the added heat, and they are very easy to break when not used by trained professionals.
The following three clarifying agents are what is most common in the industry:
Using an Enzyme
Pectin is a polysaccharide found in plant cell walls and its where the pulpy fibrous part of juice comes from. It’s not completely digestible and many food companies add pectin as a fiber like cellulose or lignin. As a result of this usage, pectin is extremely colorful and has a very rich texture. But that texture is not always desired in liquid.
Adding a little bit of pectinase will, over time, destroy these walls and get rid of much of the texture.
Because pectinase is an enzyme, the only thing adding more will do is increase the rate of reaction In fact, you will rarely need a couple of drops for a liter of juice. Other ways to speed up the reaction is to increase the temperature to around 55 degrees C. Be cautioned, if you make it too hot, you will kill the enzyme.
Using a Suspension - Positive and Negative Charged Fining Agents
Positively Charged Fining Agents
These fining agents are used to attract negative ions to them. These fining agents have “cations” which means they attract negatively charged molecules to them. Agar Agar, Gelatin are some commonly used positively charged agents.
Negatively Charged Fining Agents
In addition to using a positively charged fining agent, many brewers and fermentors use a negatively charged fining agent. These fining agents have “anions” which means they attract positively charged materials to them. The most common one of these is a material Bentonite. However, others like Silicon Dioxide are becoming extremely affordable in the processing.
You will likely need to use both of these to clarify a liquid. The reason is one fining agent will take the positively charged ones, and the other will be used for negative ions. A more complete list of these agents and there properties can be found here. For more information about Bartending Classes go here.