Cider Clarification 101

Last Updated: 4/2022

Applies to: any cidermakers looking to improve clarification practices. This article covers why clarification is important and best practices for settling with clarification products. See end for advice on choosing Scott Laboratories fining agents for cider clarification.

Why is Cider Clarification Important?

So many of the challenges cidermakers face during production can be linked with overall cider clarification. There are two main stages impacted by improper clarification:

Fermentation

Proper clarification prevents yeast stress during fermentation. High turbidity can cause yeast stress resulting in H₂S production. However, during settling, it is important not to over-clarify or yeast will struggle to stay in suspension, potentially leading to a sluggish or stuck fermentation. Ideally, juices should be clarified to 80-120 NTU or 1-2% solids.

Filtration

Proper clarification prevents issues with filtration and stability. Poorly clarified ciders may prematurely clog filter media, making it very difficult to achieve sterile filtration. Clarification of cider for filtration should start before fermentation. Attempting to clarify with only post-fermentation treatments may not be as effective.

Clarification Best Practices

Below we detail best practices for clarifying cider throughout the cidermaking process:

Pressing

Treating milled apples with enzymes improves clarity of the juice. Additionally, enzyme treatment increases the volume of free run juice and can increase the volume of juice extracted at lower pressures. A minimum of 2 hours contact time with enzymes is recommended.

Juice

Clarification of juice can be achieved in multiple ways. First, determine if juice needs to be clarified: Ideally, juices should be clarified to 80-120 NTU or 1-2% solids. If juice does need to be clarified this can be achieved via the addition of enzymes and fining agents.

Step 1: Add Enzymes

Fruit juice cloudiness post-pressing is mainly caused by pectin. Negatively charged pectin molecules form a protective layer around positively charged fruit particles, keeping them suspended. Enzymes, specifically pectinases, break down pectin, allowing fruit particles to settle and compact in the lees.

Step 2: Add Fining Agents

Fining agents such as bentonites and chitosans help speed up settling. They facilitate flocculation of fruit particles after the pectin holding them in solution has been broken down (via enzyme treatment). Once flocculation has occurred, sedimentation can commence. Bentonite-based fining agents may inactivate enzymes, so it is important to follow proper timing when working with enzymes and bentonite.

Step 3: Perform Settling or Flotation (or Centrifugation)

Physical processes like settling, flotation and centrifugation should be used as the last step of juice clarification. This process collects and compacts the fruit particle/fining agent floccules and allows clean juice to be removed. Settling and centrifugation rely on gravity, whereas flotation relies on gas injection.

Post-Fermentation

Ciders can be clarified in the same three steps detailed above. However, it is important to note that if juice has not been properly clarified prior to fermentation, it may be difficult to clarify completely post-fermentation and avoid filtration issues.

The two main factors that complicate post-fermentation clarification are:

• Temperature: Ciders may have been cold-crashed to stop fermentation. At this temperature, enzymes are inactive, and settling may be inhibited.
• Alcohol: Alcohol has a stabilizing effect on some colloidal compounds, making clarification less efficient.

Post-fermentation clarification can be achieved with enzymes, chitosan, gelatin, isinglass, bentonite, or silica gel. These products can also address other fining and stability concerns.

Choosing Clarification Products for Cider

Consult the chart below for assistance in choosing cider clarification products:

Enzymes

Fining Agents

Learn More

This article is featured in our 2023-2024 Cidermaking Handbook. Download the complete book below