I’ve been rifling through a lot of old brewing books lately in preparation for a book I’m writing. My goal, besides detailing some well-known historical styles, has been to determine the outer limits of European brewing traditions, looking for inspiration and techniques that might help us beer explorers find new and different things to drink.
One of the many things that struck me was a description of a type of dichtbier (thickbeer) called Danziger Jopenbier. This strange creature had an original gravity between 45 and 55 degrees Plato, or somewhere upwards of 1200 original gravity (OG)! Because of the high sugar content, it was murder for yeast, and the alcohol rarely got above 4 percent. The beer was not really a beverage, but more of a cross between a nourishing tonic and a culinary ingredient along the lines of balsamic vinegar.
Jopenbier was spontaneously fer-mented in mold-shrouded cellars, and scientists at the turn of the last century were able to identify brewers yeast, wine yeast and wild yeast, along with Mucor and Penicillum molds. There must also have been Lactobacillus activity, as the lactic acid content was about 2 percent—higher even than lambic.
Additionally, the scientists identified a skin-forming kamm yeast. The word kamm literally means “comb,” as Bosco’s brewer Fred Scheer told me, because it may be skimmed off the surface with a combing motion. The word also means “crest,” as in the comb of a rooster, and kamm yeasts do indeed form a film on the surface. Mention of this type of yeast occurs sporadically in the old German texts, although I can’t find an everyday drinking beer that employed it.
But why not? Some of the more adventurous beers being made are almost port-like—Cuvée de Tomme from Pizza Port’s Tomme Arthur comes to mind. Why not close the loop and introduce yeasts that will add the wonderful nutlike aroma found in port and sherry?
Let’s Give It a Shot
I should say that this recipe is strictly experimental, and that if complicated beers turn you off, you might as well turn the page right now. Here’s the plan.
We’re going to brew a strong, tawny-colored wort using an old Kulmbach mashing technique that will give us a rather under-attenuated beer. Because we’re going to expose the beer to oxidative conditions later, and because dark malt melanoidins can be involved in these oxidation reactions, potentially producing cardboardy flavors, we’re going to get much of our color from cooked sugar. This is a perfectly traditional method for beers such as the sour Flanders red ales. We’ll be adjusting the acidity and alcohol levels, and finally fermenting with sherry yeast and warm-aging it with a large amount of head space, then bottling it uncarbonated, like wine. Goofy enough for you?
This will be a two-and-a-half-gallon recipe.
Let’s start with the cooked sugar. Take 1 pound of ordinary refined white sugar and place it in a heavy saucepan or skillet with 1/4 cup of water over medium heat. Allow the sugar to melt. At a certain point, the water will boil away and the temperature of the sugar will start to rise. If you must stir, do so gently to avoid recrystallizing the sugar. After several minutes, you will notice the color start to change. Keep a careful watch on it, as the color change will happen more rapidly.
The sugar will start to smoke as it darkens, but keep going. When it reaches the color of molasses, you’re done. It will have a taste like toasted marshmallows. Now you can either dump it into your brew pot or into a pan lined with nonstick foil to let it harden for later use. It will keep indefinitely.
If you’re using extract, try to find a brand that has a low proportion of fermentables, under 70 percent. As always, freshness is very important in liquid extract. You’ll need 11 pounds of liquid, or 9.5 pounds of dry. At the start of the boil, there should be 3 gallons in the kettle.
For the Mashed Version
Use 6 pounds of Pils malt and 6 pounds of Munich malt.
The mash procedure is one that was used to produce very full, rich-tasting beers. Mash in the malt with 122 degrees F water, let’s say 1.25 quarts per pound. Add a little (1/2 to 1 gallon) boiling water to bring the temperature up to 130-132 degrees F, and then allow the mash to rest for half an hour. At this point, drain the liquid from the mash into the kettle and boil for 15 minutes, then return to the kettle, where it should bring the mash up to 162 degrees F, which is at the high end of the mashing range. After another half hour, drain the mash normally, and run off 3 gallons of wort into the kettle and boil. Because of the small batch size and desired high gravity, we will not be sparging.
To the kettle add the cooked sugar and 1.5 ounces of Northern Brewer hops (figured as whole; use 1 ounce if pellets). We are strictly looking for bitterness here and not a lot of aroma character. Boil for an hour, then cool and pitch the sherry yeast. I recommend that you use Vierka liquid sherry yeast. If your shop doesn’t carry this obscure item, just do an Internet search and you’ll come up with a supplier. You may also use dried sherry yeasts.
Conduct the primary at room temperature, between 68 and 72 degrees F. When it settles down, rack it into another carboy, and add the following ingredients for adjustment:
–2 ounces food grade lactic acid (80 percent) or equivalent;
–Alcohol, your choice of 16 ounces of 190 proof spirits; 35 ounces of 90 proof vodka, unflavored schnapps or Irish whiskey; or 40 ounces of 80 proof of the same.
These adjustments should give the yeast conditions suitable for the sherry flor to form on the surface, which helps with the development of the nutty, pleasantly oxidized flavors we’re looking for.
At this time you can add a small handful of toasted French or Hungarian oak cubes (www.stavin.com) if you like. Move the carboy to a warm place—an attic or a furnace room, because contrary to normal practice, we’re trying to oxidatively age the wine. Aging under these conditions should take from 6 months to a year. If you want to get your acidity naturally, you can use whatever Belgian wild yeast mix that strikes your fancy instead of the lactic acid, but I would expect this would add another 6 months or more to the whole process.
After this time, your brew should be bottled without carbonation. A beer of this complexity and strength should be a candidate for long aging. Just like home-brewers and fine port, it only improves with age.