Brewing Sour

January 14, 2015 By K. Florian Klemp

We have become rather smitten with sours in recent years, an affair that shows no sign of waning. The venerable examples are more attractive than ever, and brewers are embracing them passionately. This, in turn, has piqued great interest from homebrewers, who now have at hand the necessary design and ingredients.

Brewing sours by traditional means can be quite a challenge. Conversely, it’s possible to make reasonable clones without arduous, lengthy and esoteric methods. Thanks mostly to liquid yeast purveyors, these shortcuts can build a solid, useful foundation for further exploration of sour brewing. The range of sour beers available today is astounding, enough to inspire a Euro classic, stylish American or a personal interpretation of your own.

We will touch on the most rudimentary methods necessary for making Old World styles and American wild ales that showcase a predominantly sour character, another subset of “wild” brews, just as the Brettanomyces-accented beers are. As with those, the selection and handling of working cultures are of utmost importance.

Two of the largest yeast purveyors, Wyeast Laboratories and White Labs, carry an essential portfolio of yeast and bacteria as blends and individual strains for sour brewing, the main actors being, besides Saccharomyces, Lactobacillus delbrueckii, Pediococcus and Brettanomyces. These mixed cultures mimic microflora used by professional brewers for pitching, spontaneous fermentation and barrel fermentation and maturation. Organisms are proportioned and designed for each to kick in at the appropriate time, depending on pH, temperature, residual products and available nutrients from the fermentation “cascade.” Note the specs of the cultures, as they are different from those of the normal strains.

There are many ways to approach sour brewing. Here are the three most common and feasible methods:

The easiest approach is pitching an appropriate blend in the primary fermenter and let nature take over. This is preferred for more intense beers like lambic, Berliner weisse and Flanders red, since the respective fermentation periods overlap and organisms interact in more of free-flowing, dependent environment.

A second strategy is primary fermentation with standard Saccharomyces followed by a single or mixed culture afterward. This is more useful for gose, Flanders brown and American wilds, and gives more pronounced character from the primary strain, but still allows that primitive patina to shine over time.

A third method involves pitching each organism separately as the wort progresses through fermentation. This will require a bit of research to properly assess the timing, as each microbe is reliant on the other, feeding on metabolites and residuals that the others cannot.

Consider dedicating some basic equipment to sour brewing, namely non-porous fermenters, siphoning equipment and perhaps a corny keg. Also consider that carboys or cornies might be tied up for quite some time, cutting into your normal brewing schedule. Depending on the style and desired effect, several months to three years is normal.

Extract/steeped grain brewing works best with the Flanders reds and browns, as specialty malts play a significant role in crafting those.

Berliner Weisse and Gose

These two styles have really surged in popularity in recent years; they’re simple, anachronistic pale wheat beers with a sour finish contributed by Lactobacillus delbrueckii. Berliner weisse, on the brink of extinction not long ago, was the first to re-emerge. Leipziger gose followed, and is currently the hotter commodity among American microbrewers. American micro-versions of each greatly outnumber those from their native Germany.

They comprise pilsner and wheat malt, with a ratio of 60:40 an appropriate starting point. Hop rates are minuscule (single-digit IBUs), as higher levels will stifle lactic fermentation. Berliner weisse is generally the sourer of the two and traditionally tempered with sweet fruit or woodruff syrup when served. It is also made to a lower original gravity of 1.030 to 1.035, whereas gose is usually in the range of 1.050.

Ferment gose with Belgian wheat or Bavarian weizen yeast and L. delbrueckii culture (pitched either in the primary, secondary or aging vessel) and wait at least three months before packaging. White Labs WLP630, conveniently, is a mix of weizen yeast and L. delbrueckii and perfect as a primary pitching culture. Gose also contains salt and coriander, making it essentially a cross between Belgian witbier and Berliner weisse. Use 1 ounce of coriander and a teaspoon of salt per 5 gallons of wort, added late in the boil.

For Berliner weisse, I prefer altbier, Kölsch or neutral American yeast for primary fermentation, as I find the intense aromatics and flavors of weizen yeast a bit overbearing in this beer. Pitch L. delbrueckii with the primary yeast. Age 3 to 6 months post-fermentation.

Flanders Red and Brown

These have undoubtedly arisen from a common, ancestral wildly influenced beer. Both still exhibit that personality, but neither are spontaneously fermented as they were in days of yore. Instead, those rapscallions are pitched or introduced to the wort in oaken maturation barrels. Pediococcus, Lactobacillus and Brettanomyces are the three savage characters that shape the profile, Pediococcus being the primary souring strain.

Flanders red tends to be more highly attenuated than brown, often over 90 percent, and to have a more pronounced wild profile, similar to lambics in this respect. Flanders brown, sometimes called Oud Bruin, is maltier, sweeter and has more normal attenuation.

Both have substantial measures of coloring malts, including toasted base varieties such as Vienna and Munich, along with caramel, aromatic and roasted malts. Hop rates are in the mid-teens in reds (offering Lactobacillus at least a fighting chance) and browns in the mid- to upper-20 IBUs. Maize is also a common ingredient, usually at 10 to 20 percent of the grist. Reds usually run from 1.050 to 1.060 OG, and browns the same or marginally higher. Age them at least one year before serving.

The difference between the two from a basic homebrewing standpoint comes from the selection of primary and secondary fermentation cultures. For reds, I’ve used the mixed Flemish cultures from Wyeast (Roeselare 3763) or White Labs (Flemish WLP665) as the primary pitching strain with good results. The Wyeast product also has a second Saccharomyces sherry strain for additional attenuation.

Flanders browns are fermented with a slightly different strategy. I’ve used the method of fermenting first with a regular top-fermenting Belgian or German strain, followed by inoculation with either Wyeast 3763 or WLP665 for secondary fermentation and maturation. This will allow primary fermentation before introducing the wort to souring and funking bugs, arresting the attenuation, leaving a sweeter, less wild-tasting finished product.

Lambic

The traditional labor-intensive and complex production of lambic is one that even the most dedicated, skilled and indulgent homebrewer would have a tough time duplicating. Thankfully, we mortal homebrewers can make reasonable facsimiles with simple, routine methods, ingredients, proficiency levels and, of course, lots of patience.

The grist is 60-70 percent pilsner malt and 30-40 percent raw wheat (flaked will also work). Some pros still use an extensive, multi-step turbid mash schedule for starch conversion and to ensure that essential components and nutrients will be available downstream during the lengthy fermentation and maturation. A two-step infusion mash for dextrinous wort, 122 degrees F and 155 degrees F, will suffice, followed by a very hot sparge of 190 degrees F (increased extraction of sugars and starch).

Aim for wort with an OG of 1.050 to 1.060 and minimal IBUs (<10). Once the wort has been produced and chilled, pitch one of the commercial lambic cultures, Wyeast 3278 or White Labs WLP655. As with the other culture blends, these will mimic as best as possible those in traditional lambic breweries. Plan on waiting one to three years for lambic to fully mature.

As mentioned earlier, all of the mandatory organisms, Saccharomyces, Pediococcus, Lactobacillus and Brettanomyces can be purchased separately and pitched at the appropriate point if that sort of challenge seems worthwhile. Lambic and its offspring really deserve more attention than this column can offer.

American Wild Ale

An extensive number and variety of American wild ales can be found these days. Most are based on familiar Belgian-style top-fermented brews, augmented with Pedio-Lacto-Brett cultures. Many brewers are even fermenting and/or aging in barrels that host these critical critters. Many of these rival the classics in quality.

Homebrewers need not be so fancy to craft similar beers. American wild ale is a wide-open and vast family, or more appropriately, philosophy. Start with the same approach, brewing your favorite house Belgian, and age with one of the commercial mixed cultures or individual strains. Goldens, dubbels, tripels, saison and blonds have been marvelously successful in commercial U.S. breweries, and there’s no reason it couldn’t work in your brewhouse.

The interest in exotic sour and wild beers has inspired much mad experimentation in North America. This rousing success has had a ripple effect in the homebrewing community with the offering of “wild” yeast and bacteria blends. It might even spur you to investigate the more complicated brewing methods such as sour mashing, spontaneous fermentation, complex fermentation schedules, blending, dreg-culling, barrel-aging and selective inoculation. Until then, brew and enjoy a tamer version of these wild brews.

Berliner Weisse

5 gallons, All-grain, OG 1.030, 8 IBU

Do a two-step infusion mash at 122º F (30 minutes)
and 155º F (60 minutes) with 2.5# wheat malt and 3.5# pilsner malt

Sparge with 190º F water to collect wort and boil for 15 minutes

Hops: 1.5 Alpha Acid Units of German noble hops added at the
beginning of the boil, first wort hop or the mash.
This will provide between 5 and 7 IBU

Chill wort and pitch into primary fermenter Wyeast 1007 or
White Labs WLP036 and Wyeast 5335 or White Labs WLP677

Ferment for 2 weeks, rack into maturation vessel
and age for 3 to 6 months

Flanders Red

5 gallons, extract/grain, OG 1.055, 18 IBU

Steep 1# Caramunich III, 0.5# aromatic malt and 4 oz Special B malt for 20 minutes

To the steeping liquor add 2# Munich or amber LME and 5# light DME and top up with water to 6 gallons

Hop with 1 oz East Kent Golding for 60 minutes

Chill and ferment with Wyeast 3763 or White Labs WLP665
for 1 to 2 weeks

Rack into maturation vessel and age for 1 to 2 years

Optional ingredients: Reduce LME to 3# and add 4# of sour cherries at the end of primary fermentation