Old Franconia Lager

“Farmhouse beers” are a huge and fuzzy category, in my mind including everything from saison to many kveik-based concoctions to some kellerbiers. Although a character-rich and slightly wild yeast is most common, I would also think some “rustic” lagers should also qualify. Farmhouse, like so many things in homebrewing and craft beer, is a moderately mythological concept, and one built more around feelings than strict history. I suppose that’s why it’s fun to play in the space! It can stir a different set of emotions from by-the-books or paint-by-numbers brewing; it allows creativity (and I suppose role-playing) in a way that many other styles don’t, or at least in ways that differ from other styles.

I recently ran across a supplier for Isaria 1924 malt by Weyermann (William’s Brewing). I am often interested in trying base malts outside my norm, and this was a fun opportunity to experiment. The descriptions / marketing material from Weyermann state that the malt is “made from the oldest German malting barley variety Isaria, which was officially approved for the beer production in 1924. Brewers used Isaria to brew traditional, unfiltered and flavorful traditional German Lagers.”

Colorwise, Isaria 1924 weighs in at 3.5 SRM and is thus closest to most Vienna malts (3-5 SRM, depending on supplier; the Weyermann version is 3 SRM). Relative to the Weyermann flavor wheel, Isaria 1924 reads as a subdued Vienna, with similar locations of flavor/aroma peaks, but different magnitudes (e.g., a peak at “sweet” taste but an arbitrary value of 2.5 versus 4.5).

Among the recommended styles from Weyermann, Franconian landbier was near the top. This intrigued me, because I had recently read about the “style” in the Spring 2025 issue of Craft Beer and Brewing (including recipe). Why not try something in that vein?

My version is not really based on anything in particular, other than crafting a general story–something to emphasize malt and lean into a story of a rustic beer that plausibly would originate in Franconia (which primarily overlaps with northern Bavaria). I wanted to use 100 percent Isaria 1924 malt, particularly because this was my main point of the brew session. I only had 10 pounds, which might be a bit lower on gravity than I wanted for my usual 5.25 gallon batch, so I scaled down to 4.5 gallons. Spalt Spalter hops were my hop selection, because they provide a nice earthy and spicy quality that fit well with my intended “rustic” results. Finally, I wanted to give WLP860 Munich lager dry yeast another spin; as a strain that would emphasize the malt character, and that also would be consistent with my Franconian/Bavarian theme (although Munich itself is to the south of historical Franconia–we’re going for “vibes” and not authenticity here!). During my last brew with it, I learned that a bit of patience was key–WLP860 is a slow starter, and so I shouldn’t fear if signs of fermentation are delayed.

Old Franconia Lager

  • 10 lb. Isaria 1924 malt (Weyermann)
  • 0.5 tsp. BrewTanB, added to mash
  • 1.25 oz. Spalt Spalter hop pellets (4.3% alpha), 60 minute boil
  • 0.5 tsp. BrewTanB, 10 minute boil
  • 1 Whirlfloc tablet, 5 minute boil
  • 1.75 oz. Spalt Spalter hop pellets (4.3% alpha), 5 minute boil
  • 2 pkg. Munich Lager dry yeast (White Labs WLP860)

Target Parameters

  • 60 minute infusion mash, 154°, full volume mash
  • 1.051 o.g., 1.016 f.g., 4.7% abv, 29 IBU, 6 SRM
  • Claremont tapwater, neutralized to remove bicarbonates. Roughly 40 ppm Ca, 18 ppm Mg, 102 ppm Na, 50 ppm SO4, 130 ppm Cl, RA=-31
  • 4.5 gallon batch

Procedure

  • I treated 6.75 gallons of water with a Campden tablet and 6.9 mL of 88% lactic acid, in order to drop out the bicarbonates.
  • Next, I heated the strike water to 159°, added the grains, and held at 154° with recirculation for 60 minutes. After that, I raised the mash temperature to 168°, held it there for 10 minutes, and then pulled the grains.
  • In total, I collected 6 gallons of runnings with a gravity of 1.038, for 64% mash efficiency.
  • I brought the runnings to a boil, adding hops and finings per the recipe. Because my gravity was a bit lower than intended, I boiled a bit harder to bring the gravity up. After 60 minutes, I turned off the heat and chilled the wort to 69° before transferring to the fermenter.
  • I chilled the wort down to 50° in the fermentation chamber, pitching the yeast when the beer was at 60° (night of the brew day).
  • This beer was brewed on 21 September 2025; it had a starting gravity of 1.049.
  • I fermented the beer at 50 degrees; small bubbles were visible on the surface by 22 September 2025, 24 hours after pitching. By 29 September, there was a good layer of krausen on the surface. Given the slow start the last time I used this yeast, I wanted to confirm that things were moving along. I noted an aroma of sulfur in the fermentation chamber on 30 September 2025.
  • I raised the temperature of the beer to 56° on 2 October 2025, and moved the beer to ambient on 7 October 2025.
  • Using a closed transfer, I kegged the beer on 18 October 2025. At the time, it had an amazing malt flavor!
  • Final gravity was 1.013, for 4.7% abv.

Tasting

  • Appearance
    • A deep gold beer, with a very slight haze, which pours with a thick, white, and persistent head. Beautiful!
  • Aroma
    • Medium malty-rich aroma, with moderate spicy hop character. Delicate hoppiness.
  • Flavor
    • Moderate malty rich character, against a medium level of hop bitterness. Clean yeast character.
  • Mouthfeel
    • Medium-light body, moderately high carbonation, off-dry finish. There’s may be a tiny bit of astringency.
  • Would I Brew This Again?
    • This is super nice as something a little different from the “usual” lagers. Isaria 1924 stands well as a solo malt, making an interesting and highly drinkable beer. I might dial the bitterness back a touch, or else increase the gravity slightly; the aroma is amazing, but I feel that the malt character is slightly obscured. I would also do a 90 minute mash or a decoction mash in order to improve efficiency, given the lower mash yield for this particular malt.
  • Overall
    • 8/10

The Quest for a Real Jurassic Beer

Unexpected connections between my vocation of paleontology and my avocation of brewing pop up in the strangest places.

Recently, I decided to try my hand at a traditional Bohemian pilsner. While reading up on the style in order to develop my recipe, I ran across this interesting tidbit from a technical presentation by folks from Technische Universität München and Weyermann Malting Company [link to PDF]:

The most influencing process for the production of original Bohemian malt is the floor malting process after a 48 h steeping. This is done on traditional naturally cooled Solnhofen limestone floor tiles.

Solnhofen Limestone?!!! No way! My paleontologist brain went into overdrive when I read that statement. Using Solnhofen Limestone for floor tiles is the paleontological equivalent of using Kobe beef in a McDonald’s Happy Meal. Kinda sacrilegious, but also pretty awesome. Let me take a minute to explain this seemingly inane (yet exciting) detail.

Malted barley

Malted barley

First, the brewing side. Raw barley grains are turned into malt by a brief germination, which among other things creates enzymes in the grain that break down starches into more fermentable sugars later during the brewing process itself. Germination produces a lot of heat, which can be a fire hazard in some conditions (and isn’t great for the quality of the finished malt, either). So, the grain is cooled by a combination of physical turning as well as specially cooled floors. Traditionally, the cooling was accomplished by hand-turning on stone tiles (including those made from Solnhofen Limestone, apparently). This germination period is followed by a drying and kilning period, which halts germination and readies the malted barley for brewing. The malted grains are ground up, steeped in water, the resulting liquid is boiled with hops and then fermented with yeast–and bingo, you have beer!

Now, let’s talk about rocks. Solnhofen Limestone is from Bavaria, formed in warm-water lagoons during the Late Jurassic, around 150 million years ago. The gentle waters and fine-grained ooze created the conditions for exquisite preservation of any animals that died in or near the water. Soft-bodied organisms that are rarely fossilized, including dragonflies and giant shrimp, are fairly common finds. The most widely known fossils, though, are the rare and delicate flying vertebrates. Winged reptiles such as Pterodactylus are housed in museum collections globally. And then there is the most iconic fossil of all: Archaeopteryx.

Fossil of Archaeopteryx in Solnhofen Limestone. Specimen displayed at the Museum für Naturkunde (Berlin). Photo by H. Raab, CC-BY-SA.

Fossil of Archaeopteryx in Solnhofen Limestone. Specimen displayed at the Museum für Naturkunde (Berlin). Photo by H. Raab, CC-BY-SA.

First discovered in the 1850s, the early bird Archaeopteryx is a textbook example of a transitional fossil. It preserves features of its dinosaurian ancestors, including sharp teeth and a long bony tail, as well as the long flight feathers found in today’s modern birds. The fingerprints of evolution are all over Archaeopteryx, and it has been key for many discussions on the origin of birds and flight as well as their relationship with carnivorous dinosaurs. Although new discoveries in China, Mongolia, and elsewhere have filled in additional details, the Archaeopteryx skeletons from the Solnhofen Limestone remain historically and scientifically important.

Beyond its paleontological significance, the durable and fine-grained Solnhofen Limestone has a long industrial history–indeed, the fossils are basically “by-catch” from that activity. Over the centuries, the limestone has been used for sculpture, floor tiles, and printing (lithographic) plates. A connection to brewing was new to me!

In the interest of geeky beers, I wondered: was it possible to brew a beer with malt that had rested on the same rocks as Archaeopteryx–a real Jurassic beer? I knew that Bohemian malt had traditionally been malted on Solnhofen Limestone floor tiles. But was this still the case today? Time for some sleuthing.

I started my investigation with Weyermann Malting. They carry a wide range of European pilsner malts; being a modern company, their product is largely produced using state-of-the-art malting techniques in order to maintain consistency and quality. This most typically entails malting on slotted metal floors to allow efficient germination and air circulation at the appropriate times in the process. These procedures create high quality malts, but they don’t involve Solnhofen Limestone.

My eye was then drawn to their floor-malted Bohemian pilsner malt. It is billed as being “made in an original floor malting facility”. That sounded promising. A little more sleuthing found a 2009 article [PDF] about the malt by Sabine Weyermann (of the very same malting company) in Scandinavian Brewers’ Review. In this article, Weyermann notes that their floor-malted pilsner malt is produced under contract at Ferdinand Brewery and Malting Company–whose malt house is floored by Solnhofen tiles.

A view inside the traditional floor malting facility at Ferdinand Brewing and Malting. From Weyermann 2009.

A view inside the traditional floor malting facility at Ferdinand Brewing and Malting. From Weyermann 2009.

My journey to Solnhofen Beer was almost complete! I sent off a quick email to several individuals at Weyermann Malting Company, to confirm if their traditional pilsner malt that is sold today is still produced on Solnhofen Limestone. Not long after, I received a response from Stefan Gottschall at Weyermann, verifying the Solnhofen connection. My quest was complete.

So, you can brew a Solnhofen-themed beer! Thanks to Weyermann’s Floor-Malted Bohemian Pilsner Malt, every sip of my latest lager has a physical connection to Archaeopteryx and all of the other Jurassic critters of ancient Bavarian lagoons. This is beer at its best–an experience not just of taste, but also one imbued with 150 million years of history and a link to the fossils I love.

An Archaeopteryx-linked beer requires the appropriate glassware.

An Archaeopteryx-linked beer requires the appropriate glassware.