Fruit Beer: Tips from the Pros
Brewer: Peter Bouckaert
Brewery: New Belgium Brewing Co., Ft. Collins, Colo.
Years of experience: Nine
Education: Degree in biochemistry in brewery and fermentation technology from CTL
in Ghent, Belgium
House Beers: Fat Tire (amber ale), Sunshine Wheat, Old
Cherry Ale, Abbey (Belgian double abbey style), Trippel (Belgian triple abbey
style); special releases include Frambozen, Saison, Abbey Grand Cru, and Porch
Swing (single abbey style)
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After harvest New Belgium’s fruit is washed with
chlorine-free well water, screened for color, crushed, and frozen. We don’t
wash it with city water. The problem you sometimes run into when using city
water is the production of chloro-phenols, which are detectable by taste in
very low concentrations. Homebrewers who cannot get well water can use a carbon
filter.
Pasteurizing your fruit is one of the ways to reduce the
microbiological load. In general when pasteurizing, be careful of the oxygen
levels. You want to reduce the possibility of oxidation and the flavor it
produces. Reducing the size of each piece of fruit makes the process faster and
less risky.
We pasteurize the fruit for a few minutes, keeping the
temperature below 158° F. But make sure the heat distribution in the whole
batch is even. In general you need to pasteurize for a longer time at a lower
temperature if the pieces of fruit are large.
There is a risk of contamination when brewing fruit beer. A
low-risk beer would be a lambic or sour beers in general because they are
already so low in pH and so well fermented. Other beers are more risky when you
add fruit to them. Again, try to avoid using whole pieces of fruit and
pasteurize.
My experience is mostly with sour beers. They already have a
microbiological diversity and are well protected against other microbiological
contamination by low pH and lack of remaining nutrients. Fruit contact time for
those beers can be months to a year.
Here we keep the fruit in contact for four days for the Old
Cherry Ale because that has a low fruit flavor compared with other fruit beers.
Our Frambozen, on the other hand, is a very strong fruit beer, both in alcohol
and fruit content. We keep the raspberries in for about two weeks.
To avoid tart or bitter flavors we make sure we have a good
variety of fruit. You could use sugar to compensate for tartness, but the
problem with homebrewing that way is that the sugar will be fermented again. In
my experience lactic acid can mellow tart flavors. We do not add anything to
sweeten the cherry beer. But we make it so that it has a high remaining
extract, which gives it a kind of sweetness. It has been my winter favorite.
To develop the beer’s sweetness you can also use a higher
temperature in your mash, around 145° F. You can produce a certain amount of
non-fermentable sugars by playing around with mash temperatures (short or no
beta-amylase rest or mash in at 162° F) or you can use color malts or
cara-pils.
Our raspberry is quite a heavy beer. It’s the basic wort of
an abbey, 6.5 percent alcohol by volume. For the United States that’s quite a
heavy beer. It’s also quite dark. It has a high starting gravity of 16.5 Plato
(1.067 specific gravity).
To prevent the flavor of seeds and pits, they can be
screened out, as they are for our Frambozen; covered by remaining sweetness; or
reduced by flavor compounds, such as the harshness of hops with wood.
The most common mistakes people make when brewing fruit beer
have to do with microbiology and the lack of brightness. Microbiological
problems very often include diacetyl off-flavors or acid formation. You can
reduce this with proper pasteurization. There are also steps that can be taken
to reduce microbiological problems in general. Start with good overall brewing
techniques.
To prevent haze in the raspberry beer, we use different
kinds of filtration. We first use a centrifuge to remove most of the larger
particles. Then we send it twice through our DE (diatomaceous earth) filter.
We’ve been searching for other methods but without positive results.
I would recommend homebrewers use less fruit to avoid haze.
To compensate for flavor loss, look for a good, strong variety of fruit.
The Tips:
• When pasteurizing fruit, make sure the heat distribution is even.
• Mellow out tart fruit flavors with lactic acid or use of
higher temperature in your mash.
• To prevent haze fom fruit, use a filter and reduce the
amount of fruit you use.
• To prevent the flavor of seeds and pits, screen them out.
