Brewing Extract-Based Sour Beers
When I wrote American Sour Beers I ignored extract brewers (sorry), other than a brief note on page 307 about adapting all-grain recipes. I mentioned malt extract several other times, but only in the context of bolstering the fermentables of a high-gravity beer or growing and feeding microbes. With the amount of time and energy required for sour beer creation, I couldn’t justify the research brews. Luckily in the two years since publication, I’ve had the effort (or lack thereof) to brew a couple delicious malt-extract-based sour beers! Good enough to be an option for extract brewers or all-grain brewers who want to brew and age a batch at a kind relative or friend’s house!
Sour Beer Type
As with clean beers, some flavors are easier to achieve in extract-based sours than others. For example, the combination of malted wheat and Pilsner malt that produces Berliner weisse is readily available as wheat malt extract. Lambic/gueuze is brewed with 30–40% unmalted wheat, but for wort production and legal considerations rather than any substantial flavor differences; accordingly, a blend of Pilsner and wheat malt extract fits nicely. Avoid styles driven by base malts not readily available as extract or only in unsuitable combinations. Flemish reds are tricky, owing to large percentages of Munich and Vienna malts.
In general, beers that are carried by steepable specialty malts, hops, non-Reinheitsgebot ingredients, or fermentation are the easiest to pull off. Luckily, most sours feature some combination of characterful lactic acid bacteria, funky Brettanomyces, fruit, barrel-aging, and specialty malts!
As with any extract beer targeted to be pale, employ either a full-volume boil or a boil where most of the extract is added for only a few minutes at the end.
Wort Fermentability
All-grain brewers adjust mash temperature to fine-tune wort fermentability in a way that extract brewers cannot. For long-aged mixed-fermentation sour beers, most brewers employ a saccharification rest at 156–160 °F (69–71 °C). Significantly, a hot mash favors the enzyme alpha-amylase, which, in turn, produces dextrins unfermentable to brewer’s yeast. This reserves more carbohydrates for the Brettanomyces and lactic acid bacteria that thrive long after primary fermentation. Unfortunately, Laaglander, the classic low-fermentability malt extract, is no longer available.
Steeping specialty malts lowers fermentability. Although the starch in caramel/crystal malts was converted by the maltster, the resulting blend of sugars and dextrins is only about 40–50% fermentable absent mashing. Accordingly, for a style like oud bruin that usually derives character from Caramunich®, steeping it without base malt will provide dextrins. Select a glassy dextrin malt (e.g., Briess Carapils®) for styles where you want unfermentables, but not the caramel and dark fruit flavors associated with other caramel/crystal malts.
Maltodextrin powder is an essentially flavorless option for reducing fermentability. As the name might suggest, maltodextrin is composed chiefly of dextrins (glucose molecules in chains of 4 to 19 molecules). As the name might not suggest, it is usually derived from corn. As a general rule, increasing the mash temperature by 1 °F (0.56 °C) reduces fermentability by 1%. So consider replacing 4–6% of the gravity contribution from moderate-fermentability extract with maltodextrin to simulate a hot saccharification rest.
Most Brettanomyces strains produce alpha-glucosidase, an enzyme that allows them to ferment chains up to nine-glucose-molecules long (although not reliably towards the long end). Certain Pediococcus species can ferment anything on the dextrin-to-starch continuum. Maltodextrin powder sold to brewers is approximately 97% unfermentable to brewer’s yeast, so brewers often add it to the boil. Another option is to boil the maltodextrin with a little water and dose it into the fermenter, if a sample, for example, at six months reveals inadequate acidity, and gravity near 1.000.
Lactose can be used in a similar way, although it is less reliable. Roughly 50% of Brettanomyces strains possess the lock pick (the enzyme beta-glucosidase) required to hydrolyze and ferment lactose. Counterintuitively, most strains of Lactobacillus marketed to brewers have an identical issue, although if your souring culture came from a dairy source (e.g., yogurt or buttermilk) you are in luck!
Two ounces (60 g) of wheat flour in a 5-gallon (19-L) batch can help recreate the starchy wort profile of a classic turbid mash. Prepare a thin slurry with the flour and cold water to add to the boil. Mixing with water will prevent the starch from forming gluey lumps when it contacts the hot wort. Boiling gelatinizes the starch granules, causing the molecules to burst into the surrounding liquid where Pediococcus can eventually convert them into lactic acid. Alternatively, toss a half-pound (0.25 kg) of flaked oats or wheat into the boil for the last 15 minutes.
Rather than addressing the fermentability of the wort, another path is to reduce attenuation during fermentation. Either ferment with a low attenuating brewer’s yeast or halt fermentation by crash chilling.
After wort production, the process for extract sour beers is identical to all-grain. Pitch the microbes and wait; eventually choosing whether to blend, add fruit, dry hop, or package.
Your First (Extract) Sour
If you’ve never brewed a sour beer, the easiest way to dabble is to use 1-gallon (4-L) jugs. Any time you brew a wort with moderate gravity (<1.060), bitterness (<20 IBUs), and color (<25 SRM) divert some into one of the jugs after pitching the brewer’s yeast, then add bottle dregs from a favorite unpasteurized sour beer (commercial or homebrew) and/or a yeast lab’s souring blend. As you brew these beers you’ll build a library of sour beers! Taste them to learn which microbes and base beers you prefer. When you find a combination you love, brew a full-sized batch, pitching the microbes from the test batch. This approach will give you time to save up old cold-side gear to hand-down to your sours!
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Golden Boy Lambic
(5 gallons/19 L, extract only)
OG = 1.051 FG = 1.005
IBU = 10 SRM = 5 ABV = 6.2%
This recipe was inspired by Steve Piatz’s “Lambic Brewing,” BYO October 2004. Brewed the day of Super Bowl XLIX. The tart result has bright lemon and subtle mineral without too much “stallion cover.” Body is slightly fuller than my all-grain attempts.
Ingredients
2.7 lbs. (1.2 kg) Muntons wheat dried malt extract
2.7 lbs. (1.2 kg) Briess Pilsen dried malt extract
0.33 lb. (150 g) maltodextrin
2.6 AAU aged Mt. Hood hops (first wort hop) (2.6 oz./74 g at 1% alpha acids)
1⁄2 tsp. yeast nutrient (15 min.)
The Yeast Bay (Mélange – Sour Blend), White Labs WLP655 (Belgian Sour Mix 1), or Wyeast 3278 (Belgian Lambic Blend)
3⁄4 cup corn sugar (if priming)
Step by Step
Mix dried malt extract and maltodextrin with 7 gallons (26.5 L) hot water, then boil for 120 minutes.
This recipe utilizes whole hops aged open for seven years. Some stores also sell “lambic” or “aged hops,” which would work well. If neither of these options are available, you can instead add a low-alpha-acid variety and reduce boil to 60 minutes.
At the end of the boil, leave lid off and chill naturally open to the air until below 75 °F (24 °C)
— ideally either outside during cool weather or where your beer ferments. Then rack to a fermenter and shake to aerate. Pitch yeast and ferment at 67 °F (19 °C) ambient temperature. Leave in primary fermenter until the gravity is stable month-over-month (9 to 24 months). Prime and bottle as
is, or blend, rack onto fruit.
If you decide to rack onto fruit, my personal favorites are white nectarines or peaches, but sour cherries or raspberries would be more traditional and work out well. For whole fruit that has been frozen/thawed in an aged sour, 6-8 weeks is my standard.
Fruit Compote Porter
(5 gallons/19 L, extract with grains)
OG = 1.055 FG = 1.012
IBU = 5 SRM = 30 ABV = 5.9%
Sour porter with blackberries and plums, soured with Lactobacillus in the absence of Brettanomyces. Lactobacillus thrives early, so no need to make a highly-unfermentable wort. Mild roast, nice lactic tartness, and jammy berries with enough sweetness to balance the acidity.
Ingredients
3.3 lbs. (1.5 kg) Briess CBW® rye liquid malt extract
2.5 lbs. (1.13 kg) Muntons wheat dried malt extract
0.75 lb. (0.34 kg) Weyermann Caramunich® II malt (45 °L)
0.5 lb. (0.23 kg) Weyermann chocolate rye malt (250 °L)
0.5 lb. (0.23 kg) Briess roasted barley (300 °L)
0.5 lb. (0.23 kg) Briess Extra Special malt (130 °L)
1.75 AAU Czech Saaz hops (35 min.)
(0.5 oz./14 g at 3.5% alpha acids)
1⁄2 Whirlfloc tablet (15 min.)
1⁄2 tsp. yeast nutrients (15 min.)
3.75 lbs. (1.7 kg) blackberries
1 lb. (0.45 kg) plums
6 oak cubes (soaked in Calvados)
Wyeast 3209-PC (Oud Bruin Blend), White Labs WLP665 (Flemish Ale), or East Coast Yeast ECY02
(Flemish Ale)
3⁄4 cup corn sugar (if priming)
Step by Step
Steep specialty grains at 165 °F (74 °C) in 3 gallons (11.4 L) of water for 30 minutes. Top-off to your pre-boil volume and add 2 g of CaCl2. Add extracts and boil 40 minutes, adding hops and other ingredients as noted.
Chill to 73 °F (23 °C). Shake to aerate, and pitch the yeast. If none of the listed yeasts are available, pitch Lactobacillus brevis and a Belgian ale strain of your choice. Hold fermenting beer close to 73 °F
(23 °C) ambient. When fermentation is complete, transfer onto fruit (I used store-bought frozen blackberries and homegrown Cape Cod beach plums), and six oak cubes soaked in Calvados plus 1 oz. (30 mL) of the steeping liquor. For whole fruit that has been frozen/thawed in an aged sour, 6-8 weeks is my standard. Prime and bottle or keg as normal.