Pectic enzyme in fruit beer recipes

This question reminds me of one of the goofiest names I ever gave a batch of beer — Strawberry Fields For Alever. It was a wheat beer with strawberries added after primary fermentation was complete, and it had an interesting pink, cloudy appearance with a nice, fruity nose. I like adding fruit to beer after primary fermentation because of the good retention of fresh fruit aromas and colors. If fruit is added to the primary, special care must be used to prevent potential carboy bombs. The fermentation lock can get plugged and pressure can build up inside the fermenter. The safest method is to ferment the beer in a plastic bucket with a large lid and an airlock. A blow-off tube on a carboy can also be used, but it too can clog and this can be dangerous.

The last two issues of BYO — the July-August 2002 issue and the September 2002 issue — contained a two-part article on fruit beers. Check these out for information on formulating and brewing fruit beers. I will tackle the question regarding pectin here. Pectin is a type of carbohydrate found in fruits that act as a structural member of the fruit, kind of like beta glucan in cereal grains. In cooking, pectin is useful for its ability to form a gel when heated in a sugar solution with a low pH. This is why jams and jellies are thick and stay on your toast or bagel instead of running off.

Although all fruits contain some pectin, many do not contain enough for making jams and jellies and many fruit spreads use pectin from other sources than the fruit being used. Certain varieties of apples, such as Granny Smith, are well-known for their especially high pectin contents.

When it comes to brewing and winemaking, pectin levels are usually kept low for two main reasons. The first is the haze pectin can cause; pectin hazes are due to the very large size of the pectin molecule and the tendency for the molecule to form gels. This is analogous to starch hazes. This is a cosmetic issue that some of us don’t worry too much about, depending on the beer style being made. My strawberry wheat beer was cloudy, but wheat beers are typically cloudy and the cloud looked cool in that beer. Cloudiness, these days, is in fashion and some of those wimpy malternatives, like Smirnoff Ice and Mike’s Hard Lemonade, actually include ingredients to make them permanently cloudy. A friend of mine was in a brewery that was making — I dare not use the term “brewing” — some of these things and he saw a big container of something called “cloud.” This was the special ingredient to make it look interesting. When you make a fruit beer at home, you can omit the “cloud.”

The other thing about pectin is that filtration becomes very, very difficult. The reason for this is again the large size of the molecule and its gelling properties. I make a hard cider every year. A couple of years ago I set up the filter, sent the cider to it as I had done in the past and wham! — the flow immediately slowed to a stop in a matter of seconds. When the filter was broken down, there was a distinctive orange film on the filter. Although the film was thin, it was so tight that cider simply could not pass through it.

The solution to this problem was to buy a liquid pectinase that I then added to the cider. Pectinase enzymes reduce the size of the pectin molecule and also prevent the fragments from gelling. About a week later, filtration was a breeze. What I should have done was to perform an easy test for pectin before filtration. To check for the presence of pectin, simply add one part of the wort, beer or wine to one part 70% alcohol. Ethanol and iso-propanol both work. I use iso-propanol (rubbing alcohol) because it’s cheap. This test will cause pectin to gel. When this occurs, the sample becomes cloudy and the pectin begins to precipitate and will eventually settle on the bottom of the sample glass.

Although this method is not quantitative, you can get a feel for the pectin concentration. If the haze is detectable, but very slight, you may decide not to worry. If the sample looks like orange juice after adding the alcohol, you probably will choose to deal with the pectin. Fortunately, it’s simple to address this problem. The easiest thing to do is to add some pectinase to the fruit mush before adding the fruit to your beer. You can use dry or liquid pectinase — follow the recommendations with the enzyme regarding usage rate. The other approach to take, especially if you don’t like adding stuff unnecessarily to your beer, is to do a test after fermentation is complete and the fruit has been added. If the sample indicates a pectin problem, then add your enzyme at this stage.

As I stated earlier, all fruits contain some pectin. According to my handydandy book entitled “Preserving” (1981, Time-Life Books), tart apples, citrus fruits, cranberries, currants, gooseberries and sour plums all have “high” pectin levels. Interestingly, all of these fruits also rank high in natural acid levels and these fruits make great jams and jellies without requiring an exogenous (outside) source of pectin. Strawberries, peaches, pear, pineapple, apricots and rhubarb all have a low pectin content. Cherries, blueberries, blackberries and raspberries all have a medium level of pectin. I think I see a pattern here — it seems like brewers typically make fruit beers with fruits that have a low-to-medium pectin level. Makes sense to me!

Response by Ashton Lewis.