by Mike Retzlaff
In BREWING LAMBIC BEER, I wrote about home-brewing an age-old style from Belgium. This time we’ll add fruit to the fermenter and make a Fruit Lambic. The Belgians make fruit Lambics by adding crushed fruit to the fermenting beer and the sugars in it ferment along with the beer. These brewers take advantage of the various wild yeasts and bacteria which come from the air, wooden kegs, fruit, and occasionally from the wooden beams on the ceiling of the brewery. These wild organisms add their own component of flavor and aroma. Over hundreds of years, the Belgians have proved their process works.
Traditional fruit Lambics include:
Kriek (sour cherries), Pêche (peach), Cassis (blackcurrent), Druif (Muscat grapes), Aardbei (strawberry), and Framboise (raspberry). Most of these, using whole fruit, require about 1.67# per gallon. As concentrated puree @ 65o Brix – 6 to 10 oz. per gallon.
Modern fruit Lambics include:
Ananas (pineapple), Pomme (apple), Banane (banana), Abricot (apricot), Prune (plum), Plaquebière (cloudberry), Citron (lemon), and Myrtille (blueberry). The amount required depends on the sugar content and intensity of aroma/flavor.
If you are not relying on a spontaneous inoculation (id est – you don’t live in the Zenne valley around Brussels, aren’t ready and willing to find out if your native flora is up to the task and won’t poison you), what remains is using one of the prepared cultures from a Yeast laboratory. Some specific strains may be gotten individually but some of these are blends of various yeasts and bacteria. Keep in mind that some of these organisms are very slow working and may take a year or more to complete their mission.
First, start by brewing a Lambic. When this has fermented for a week, add the fruit (crushed, puree, or juice), packaged cultures, and boiled oak slats. Ferment for another 6 months minimum. See Brewing Lambic Beer for more detail. The traditional method is a spontaneous inoculation which equates to under pitching. The organisms grow slowly resulting in a very slow fermentation. In many of the Belgian breweries, the fermenting beer is six months old when the fruit is added and a re-fermentation begins. When this is substantially complete, the keg is bunged and aged for 3 to 6 months. Then the beer is filtered and bottled with a young, actively fermenting beer as krausening. They are released for sale after another year in the bottle. The FG will be in the 1.006 – 1.018 SG range.
When bottling, just add a little fresh yeast (Safale US-05) and priming sugar to achieve 2.5 to 3.5 volumes of CO2. Use cork finished, champagne, or European ½ liter style bottles as you don’t want bottle grenades! Give the bottles between 2 months and 2 years to condition. (I told you it was a slow process.)
In preparing the fresh fruit, wash and de-stem before freezing. Freezing will rupture the cell walls and you’ll get more juice. It is highly advisable to treat the fruit to kill off bacteria, bugs, and wild yeasts by using sodium metabisulfate (campden). After standing for 24 hrs, the “sanitized” fruit is added to the fermenter. The fruit will provide more alcohol, body, and mouthfeel besides aroma and flavor.
In selecting what fruit you wish to add, remember that even unconventional fruit can be used. Almost every locale has figs, dewberries, blackberries, mulberries, kumquats, loquats (Japanese plums) or some other fruits and most can certainly be used in this style of beer. As a home-brewer, it’s pretty much up to you. Your actions probably won’t adversely affect the Belgian Brewing Industry and the beer police aren’t watching that closely.
If you’ve got the time, a curious nature, and an extra ferment vessel, give it a shot and see what happens!
Crescent City Brew Talk 