Schwarz 2.0 – Split Batch Temperature Experiment

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It is no secret that Schwarzbier is a bit of a white whale for me (irony duly noted). Dark and smooth with a crisp toasty breadiness, Schwarzbier straddles the line between malty and hoppy while remaining balanced and crushable. Why am I so obsessed? Besides being a noted lagerhead, Schwarzbier satisfies my innate desire as a homebrewer to brew beers that I otherwise would never be able to find “in the wild.” But who am I kidding, really? I love brewing Schwarzbier because it gives me statistically one of the highest chances of advancing to the final round of the National Homebrew Competition 👌. Previous attempts of mine either turned out too roasty, like a porter, or too dry and austere, not even worth a full writeup. But as they say: practice makes perfect and I feel like I am getting really close.

Having been interested in performing my own split batch experiments for a while, my wife graciously gifted me a set of three gallon Better Bottles as well as a set of 2.5 gallon ball lock kegs so I could split my typical 5.5 gallon batches. I figured why not kill two birds with one stone? This Schwarzbier is the first of what I hope will be a great many split batch experiments of varying levels of scientific significance.

Lager Fermentation Temperature Experiment

I think most folks would agree that Marshall and the crew over at Brulosophy have really changed the game when it comes to homebrewing practices. They have done well to show us that there is a wide gap between what the Brewing Lords hath decreed and the “proof of the pudding is in the triangle testing” realities. One aspect that we have jived on for a while now is that lager fermentations are more traditional than practical, most notably it terms of fermentation temperature.

Every lager batch I brew I push my temps a bit higher, desperately seeking “the line” where the lager has obviously gone off the rails. To that end, I thought it would be an interesting experiment to evaluate the extreme case of lager fermentation temps and what would happen if I pitched cold and then completely removed temperature controls. Why should the Brü Crew have all the fun?

Hypothesis

If most off-flavors are generated during the lag and reproduction phases, then cold pitching a large, heathy batch of yeast–ensuring those phases are sufficiently cool–means that later stages do not require rigorous temperature control.

Chilling both batches to 48ºF

Method

5.5 post-boil gallons of the same batch of Schwarzbier will be equally split between two 3 gallon Better Bottles. Both batches will be chilled to 48ºF, oxygenated for 60 seconds with pure O2, and each pitched a decanted 1L starter. One will be held at standard lager temps (a slow ramp from 50ºF to 55ºF before a diacetyl rest) and the other will be placed in my “cellar” (the small space below the stairs) without temperature control (~68ºF this time of year).

Cold: 16 hours

Warm: 16 hours

Warm: Max temp reading

Schwarz, 2.0

This is Schwarz 4.5 or so, but I never bothered to write the other batches up. My goal was to remain clean and crisp while hitting some moderate bready notes and moderate spicy hop character. I am excited to test out Sterling hops–sometimes described as “Super Saaz”–which I have heard lots of good feedback about.

Cold: Left | Warm: Right

Tasting Notes

Follow along with the BJCP guide for Schwarzbier [PDF].

Aroma

Cold – Moderately bready malt with some light crackery and coffee/chocolate notes. Low spicy hop character with a dash of citrusy essence in the background. Clean & crisp with no sulphur or ester.

Warm – Low bready malt that seems less rich than the cold fermented version, just a hint of chocolate. Low spicy hops and no detectable citrus. No sulphur, but a low pear ester and maybe a bare hint of alcohol in the tail end. Not hot or an ester bomb, but not as clean as the cold fermented version.

Appearance

Cold – A crystal clear dark brown with some faint ruby highlights. Moderate fluffy tan head with good retention and lacing.

Warm – A crystal clear dark brown with some faint ruby highlights. Moderate fluffy tan head with good retention and lacing. Pretty much the same as the cold version, but maybe my eyes are playing tricks on me: the head is maybe a teensy bit darker?

Flavor

Cold – Moderate bread-crust malt character with low cracker and chocolate notes with a low richness. Moderate-low bitterness with a moderate-low spicy hop character and again, a hint of citrus. Balance is mostly neutral, but leans a little toward the malt. Clean, no sulphur or esters. Smooth finish and no harsh roasty notes.

Warm – Low bread-crust and cracker malt notes, just the faintest notes of chocolate. Moderate-low bitterness and low spicy hop character without the citrus notes found in the cold version. Balance is more equally neutral than the cold version. Generally clean, no sulphur, but moderate-low pear esters are evident as it warms up (very low when cold). A dash of alcohol, but by no means hot. Smooth finish and no harsh roasty notes. Part of me wonders if the more vigorous fermentation “blew off” some of the deeper complexity that seems to be missing from this version.

Mouthfeel

Cold – Moderate-high carbonation and medium body. No creaminess or alcohol warming. Smooth & crisp finish, no harsh roasty or astringent character anywhere throughout the sip.

Warm – Moderate-high carbonation and medium-light body. No creaminess, but a low alcohol warmth. Mostly-smooth & crisp finish, no harsh roasty notes, but there’s a little bit of astringency in the back end. The finish is not harsh, per se, but when sampled next to the cold version it is clearly not as smooth.

Cold: Left | Warm: Right

Overall Impression

Cold – Finally, after years of trying, I have made the Schwarzbier I have always wanted to make. This attempt I finally hit that middle ground between clean and malty, bitter and smooth. There is just enough bready malt and spicy hop character to bridge the gap between Pilsner and Dunkel while remaining megasmooth and drinkable. I think in the future, if I decide to change anything, would be to either reduce the Munich to 20% or raise the bitterness by another 5 IBU. Otherwise, I am very pleased with this result and feel confident it should place well in AFC and NHC. I am also pleased with the character of the Sterling hops, an underrated American hop variety that I plan on using much more for my lagers in the future.

Warm – To be honest, I thought this version was going to be a train-wreck. Well, that is not entirely true, I knew from my previous efforts at pushing lager temps that warm ferments were less of an issue than many folks believe. However, minus the cool pitch, I thought absolutely no temp control would lead this version into dumpster territory. Instead, what I got was a version that, while not as super clean and smooth as the cold version, is actually better than many US brewed craft lagers I have sampled. At room temperature I could certainly tell the difference side-by-side, but when cold it was very easy to mistake the two.

Considering that preference for this version (see below) was exactly evenly split with the cold version shows that most folks agreed that it was passible. I hope this result encourages folks to try their hand at brewing a lager even if they do not have sophisticated refrigeration and temperature control. I would wager that if you pitched cold and were able to keep max temps within the mid 60’s–easily obtainable with swamp coolers and the like–no one would be able to tell the difference!

Other Notes

Both batches finished within a half a gravity point of each other. Minus flocing your yeast out such they finish too early, it seems wort attenuation might be much more independent of fermentation schedule than many folks might believe.

Cold: Final Gravity – 1.0135

Warm: Final Gravity – 1.013

Survey Results

Not content with merely relying on my own analysis of the two Schwarzbiers, I shared the two versions with the members of the Society of Barley Engineers. I did not have the capacity to do a triangle test, but to be honest, I am more interested in preference over statistical significance. Blind to the nature of the experiment, I had everyone fill out a simple online survey asking: “Which Schwarzbier did you prefer?” and some optional comments about what they thought the difference is. Here are the responses:

Triangle: Cold | Diamond: Warm

Hah! I love this so much, an even tie! A handful of astute tasters thought the difference was either yeast strain or temperature based on subtle fruitiness, but for the most part most folks could barely tell a difference. Included below is a sampling of the responses.

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