Nearly every fruit wine recipe calls for pectic enzymes to be added but what do they really do? How do the work? Are there any safety concerns when working with this additive? Let’s find out.

Pectic enzymes break down the pectin found between the primary and secondary cell walls of grape cells.

Pectin is located between the primary and secondary cell walls. Click for a larger image.

Pectic enzyme, also known as pectinase, is a protein that is used to break down pectin, a jelly like glue that holds plant cells together. In wines pectin can cause troublesome “pectin haze” that is not easily cleared without the use of pectic enzymes.

While this enzyme does occur naturally in grapes as well as yeast there is not enough of it to overcome the amount of pectin present in the must. Other sources of pectic enzyme include plants, bacteria, and fungus.

It turns out that fungus produces a special kind of pectic enzyme that is particularly adept at breaking down pectin even in the harsh environment created during fermentation. Most commercially sold pectic enzymes come from fungus.

Pectic enzymes may be purchased in a liquid form or as a powder at any home brewing supply store.

What do Pectic Enzymes Do?

As previously mentioned pectic enzymes break down pectin found in fresh fruit. This serves two purposes. First it helps prevent a pectic haze from forming so that the wine is easier to clear. Additionally these enzymes help in the extraction of color and juice from fresh fruits.

Commercial wineries will often toss in pectinase with their grapes during maceration to increase the amount of juice they can extract. This helps them maximize the amount of wine they can produce from a given amount of grapes.

An unfortunate side effect of using pectic enzymes is that they can speed up the maturation of finished wines. Care must be taken when bulk aging the wine to make sure that it doesn’t over mature before it is bottled. This can lead to flat wines that come across as being past their prime.

When pectin is broken down by the enzymes it produces methanol. This can be hazardous if taken in large quantities. A lot of the research I saw though showed that you would have to consume ridiculously huge amounts of wine treated with pectic enzymes before this would become an issue. We’re talking about thousands of liters of wine.

Working With Pectic Enzymes

You’ll want to use pectic enzymes any time you are making wine from fresh fruit, even grapes. As we discussed this will improve color, tannins, and juice extraction as well as prevent pectic hazes.

Typically the enzymes are mixed in with the must prior to starting fermentation. This gives them time to interact with the fruit and break down the pectin in the skins. With all the good stuff extracted yeast can then take all of that and produce a cohesive final product.

According to Alison Crowe in The Winemaker’s Answer Book you should not add pectic enzymes within 12 hours of adding sulfur dioxide or bentonite. The sulfur dioxide can reduce the effectiveness of the enzymes. Depending upon your wine making references the jury is still out on whether or not this is true. Some wine makers believe that there are no problems when adding both at the same time. Personally, I trust Ms. Crowe and will heed her warnings until I am convinced it is safe.

The effectiveness of pectic enzyme is impacted by both alcohol concentration and the temperature of the wine. High alcohol levels and low temperatures each negatively impact the enzymes ability to break down pectin.

High alcohol and high fermentation temperatures on the other hand can lead to increased methanol production which may not be good for your health. Thus it’s a good idea to keep your fermentation temperatures in the typical recommended ranges to avoid these issues. The use of these enzymes is regulated in the US and Europe. Take this as a warning to carefully measure your pectic enzyme doses.

If all this bothers you you can certainly leave the enzymes out. However, your wine’s color, flavor, and quantity will be reduced. These enzymes have been safely used since the 1960’s in just about all commercially produced wine.

Sketch by: Caroline Dahl

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