Wild Yeast Culture Experiments - Update and Recipes

I have yet to publish notes on several of my sour beer experiments, so I thought I would give one large update on several works-in-progress. Before leaving for NHC, I tasted all of the batches and recorded notes to reference during my presentation and to start planning storage and/or fruit additions.

Though I'm grouping them together, I learned (and am still learning) a great deal from each brew. So far, 2 of 5 batches have been dumped, both of which for the same reason: unpalatable levels of DMS.

DMS can be produced by some wild microorganisms, but I am confident the starchy, corncob-like flavor in these beers was created in the mash tun/kettle. DMS is fairly volatile, but since I did not boil either of these batches, the DMS that formed was not driven off and remained in the finished beer. After boiling half of one of these batches proved effective in removing the off-flavor, I concluded that a full boil is necessary to produce clean beer at the SHPB, especially those with a considerable amount of Pilsner malt.

I specify this necessity is unique to my brewery, as I have read about (and tasted) clean, corncob-free examples of low-gravity, light-colored beers produced without boiling. Perhaps a faster chilling method will make this method a reality for me (I've had my eye on a Blichmann Therminator for awhile!).

Though no-boil Berliner Weisse (and the like) is a definite possibility, I have also come across numerous commercial and homebrew with high levels of DMS. To significantly reduce the risk of DMS in the finished beer, I recommend boiling as normal. Even a small amount of DMS is perceivable (and overwhelming) in this light and simple style. In the re-boiled batch mentioned, color pickup was minimal, and will be even less in a steam-jacket kettle.

Sour Brown

Split batch of oatmeal brown (the other half was served during our wedding).

Brew Date	11/11/12
OG	1.062
Grist	16 lbs Rahr 2-row (61.5%) 3 lbs Briess Victory (11.5%) 2 lbs Flaked Oats (7.7%) 2 lbs C-60L (7.7%) 1.75 lbs Pale Chocolate (6.7%) 1.25 lbs Debittered Black Malt (4.8%)
Hops	35 IBU Apollo (60 min)
Primary Yeast	N/A
Conditioning	Inoculated with 3 shots of American Wild Ale (11/11/12) Pitched 500mL lacto slurry (02/25/13) Pitched dregs from 3F Gold Blend (early June)

Tasting notes:

02/22/13

Very musty, Not much acidity. Drier than the original but not completely attenuated. Needs a lot more time.

04/19/13

Solid pellicle has formed. Aroma is complex, but still has some stinky, blue cheese notes. Very tart, with cherry pie, fruity flavors, and some musty flavors. Thin. Needs another few months.

06/24/13

Chocolatey aroma. Acidity is picking up; a nice level for a sour brown, with still some residual sweetness at the end of the swallow. There is astringency, probably from the significant amount of ‘junk’ in the sample – yeast, trub, pellicle, etc. Maybe a slight alcohol note, but that could be the combo of the acid and the astringency. OK overall, headed in the right direction, will continue to age and see what happens.

No-Boil Berliner Weisse

Split batch of Saison wort – this half was taken off after bringing the wort to boil.

Brew Date	02/24/13
OG	1.056
Grist	15 lbs Castle Pilsner (68.2%) 6 lbs Flaked Wheat (27.3%) 1 lb Aromatic Malt (4.5%)
Hops	None
Primary Yeast	N/A
Conditioning	Lacto Slurry, mixed culture slurry, Madam Rose 2012 dregs (02/24/13)

Tasting notes:

03/06/13

SG = 1.011 (6.0%). Very aromatic. A hint of lemon, but dominated by a nutty aroma (maybe peanut butter? Also similar to the aroma of UCBC’s Winged Nut). Prickling acidity, not as forceful as I’d like but very pleasant. Nutty flavors are also present, some wheat cracker from the wheat. Simple, but extremely enjoyable already. Great candidate for dry-hopping (Amarillo? Chinook?).

06/24/13

Tasting from keg. Keg was chilled for a period of time. In that time, tasting revealed ‘nutty’ flavor as DMS

Nutty aroma/flavor (DMS) still present at similar levels to prior tastings. I don’t believe it will ‘drop out’. It’s a shame – the acidity level is wonderful. Otherwise a very nice beer.

07/15/13
Dumped keg.

Golden Sour 1 – Double Batch

A double batch (10 gal) of low gravity, malt-based wort. No boil initially, one half was boiled after primary fermentation to reduce the (extremely) high levels of DMS. The other half never recovered.

Brew Date	03/24/13
OG	1.043
Grist	9 lbs Castle Pilsner Malt (47.4%) 9 lbs Rahr Pale Malt (47.4%) 1 lbs Flaked Oats (5.3%)
Hops	None (Heated to 170F)
Primary Yeast	A – Lactobacillus (slurry from growler culture), 3711 (after souring) B – Dregs from No-boil Berliner weisse (before re-boil)
Conditioning	A – N/A B – WY3522 (Ardennes), WL644 (Brett Brux Trois) – after sour, boil

Fermentation/Tasting notes:

03/29/13

A: No bubbles in airlock throughout the week. SG = 1.021. White foamy “krausen”. Sample was very cloudy. Very odd aroma, off-putting (corn stalk - DMS?), carries through in the flavor. Fairly tart, but lacks tartness of a Berliner Weisse. Not much to it other than that.

B: Bubbled vigorously in airlock for ~ 2 days. SG = 1.030. More corn stalk in flavor and aroma than A. Not nearly as sour. Aweful.

03/30/13

B: Boiled for 90 minutes (down to 3.1 gal), added whirlfloc tablet at 15 min left, added 1 gal distilled H2O at KO. Left open to cool to 140F, then covered (flies started to swarm).

04/03/13:

A: Added 1 smack pack 3711 (French Saison)

B: Added 1 smack pack 3522 (Belg Ardennes), Brett Brux Trois (WL culture), mixed culture

04/10/13

A: SG = 1.010. Still very cloudy, much more so than B (looks like thin buttermilk). Corncob in the nose, but has diminished and fades more quickly. Still very tart, and now light on the palate, which leaves less slickness to carry the corncob flavor. The corn flavor is still there, but in lesser quantity. Not much else to the flavor. Prickly acidity on the tongue (more acidic than B, I like this level better). No yeast flavors/aromas.

B: SG = 1.012. Cloudy. Tart, thinner (will be nice with carbonation). Corny flavor is yielding to a crackery, bready flavor (graham/saltine?). Acidity is very pleasant, but I believe it would be more so if further attenuated. The carbonation may give this effect. I’m mostly surprised at the lack of yeast character after fermentation. Maybe it was because of the low fermentation temp (ambient ~ 62F), but I assumed the low pH would stress the yeast and cause some sort of flavor compound, good or bad.

06/24/13

A: Developed a thin, translucent pellicle in bucket. Flavors developing but covered up by DMS. Still gross.

B: Formed ¼” thick white, knobby pellicle in carboy. Not much aroma. Acidity is sharp and lemony, but not much else in terms of flavor. Fairly clean, with a tiny hint of DMS left. Great candidate for fruit (especially in the 1/3-full carboy!).

07/14/13: Dumped A

Golden Sour 2

Brew Date	04/07/13
OG	1.060
Grist	9 lbs Rahr Pale Malt (47.4%) 5 lbs Castle Pilsner Malt (26.3%) 5 lbs Weyermann Wheat Malt (26.3%)
Hops	None (85 minute boil to reduce DMS)
Primary Yeast	Lactobacillus (starting at 110F, apple juice/grain starter). Bucket was left in fridge for a few weeks. Developed sharp acidity in 1-2 weeks.
Conditioning	Wild yeast?

Tasting notes:

06/24/13

Developed thin, translucent pellicle (from either wild yeast in bucket or Lacto starter). Caramel apple aroma. Toasty malt flavor with sharp, lingering acidity. Hints of apple in aroma/flavor from lacto starter (made with apple juice).  Otherwise clean. Another great candidate for fruit!

07/14/13

Racked ½ of batch (~2.5 gal) on 6 lbs of whole, pitted apricots and golden apricots from Farmers Market. Fruit was washed with luke-warm water before pitting. Added ~ ¼ cup slurry from Cantillion Iris Brett C1 (from BKYeast) and mixed starter to fruit portion.

I will most likely add fruit to the (currently) plain portion as well. I have some canned raspberry puree, but I am thinking about adding a comparable amount of canned apricot puree from my LHBS to evaluate the differences of fresh fruit vs. canned puree. More updates to come! 

  

Wild Yeast Culture Experiments - Dregs in Kegs

I have quite a few sour beers in kegs. In fact, this is where most of my 'wild' projects end up. Some of my sour beers are also born in the keg, as I'm often inoculating an unexciting base beer with a mixed culture or transferring it to a keg with mixed dregs. Today I preformed the former, transferring a keg of Double Chocolate Brown to a keg holding the dregs of last year's Sour/Funky Tripel, a beer that placed third at the Indiana Brewers Cup as a Belgian Specialty Ale. Aside from freeing up a keg for an Imperial Stout that will soon be ready, I wanted to add some depth to this Double Brown. I enjoyed having it on tap but thought it was a bit one-dimensional, probably because I let the beer set on cocoa nibs for three weeks! I hope the complexities this bunch of wild yeast produce will create a few more dimensions for this beer.

If given the choice, I would much rather age my sour/funky beers, imperial beers, and lagers in a keg than a glass carboy or Better Bottle. Keg conditioning has several advantages:

It frees up both fermentor and floor space. I am able to stash my slender kegs in a corner of the basement or in my kegerator for cold-conditioning. I can stash about six kegs in the same space  as two 5-gallon carboys.

Oxygen pickup is minimized or eliminated. Sampling, bottling, splitting batches, and adding fruit/spices/oak/etc. are all common procedures that can introduce oxygen. The ability to purge the headspace and transfer under pressure is a substantial advantage.

Bottling is not required and is much easier if you choose to do so. You can either carbonate naturally or with CO2 pressure. If you choose natural carbonation (which I prefer for sour beers), the priming sugar can be evenly dispersed by adding it to the keg, capping and purging the headspace, and then shaking to combine. Bottling from a keg gives the option to bottle a small portion of the batch (a few bottles to take to a party or enter a competition). In addition to the reduction of oxygen pickup, bottling day is also made easier with a counter-pressure filler or Blichmann Beer Gun.

Experimentation with oak, spices, and hops is much easier to conduct in kegs. The ingredient can be added in a muslin bag for retrieval. Many attach a string and run it through the lid, but I've can't get it to seal this way. I've resorted to using fishing line and an unused bobber, which actually works well! In the case of oak, the chips or cubes can be retrieved from the keg and used to inoculate another batch.

Keeping beers in kegs allows them to be ready for blending at any time. Pulling samples for any size tasting panel is a breeze, and the proportions transferred into the blend keg can easily be monitored using a scale or a level strip.

Kegs are sturdy. Any time I can reduce the risk of dropping and spilling five gallons of well-aged homebrew, along with potential injury, I jump on it!

Sour beer on tap is a beautiful thing.

In my opinion, keeping your sour and funky beers in kegs is the easiest way to separate your wild brews from your clean ones, minimizing exposed soft parts and keeping mixed fermentations contained within stainless vessels. I have, for the most part, managed to keep a repository of sour-only kegs, but I have reconditioned sour kegs for clean service without issue, replacing the o-rings and poppet valves. I imagine I will soon need to keg more sour homebrew as my experiments are ready, so I will keep a log of my kegs to trace any sour/funky crossover. Kegs and their permanent components are stainless, so with good sanitation and regular maintenance I feel confident I can keep my clean beers clean and my funky beers funky (in a good way).

Here is a few items to get you started:

Suggested equipment (in addition to a basic kegging setup):

• Extra sets of poppets and o-rings
• Out-to-Out transfer line (shown in above picture), to transfer beer from a clean keg to a sour keg.
• Bottle filler

Cool to have, but not necessary:

• Additional kegs for sour beer only.
• pH meter for measuring finished beer pH
• Level strips or scale for measuring transfer volume
• Stencil to mark and identify sour/funky kegs. Insignia may include simple text ("sour", "wild", "funky", "brett only", "no pedio", etc.) or a simple graphic (Jolly Roger, pitch fork, effigy of George Clinton).

What kind of homebrewed treasures do you have tucked away in a forgotten Cornie?

Wild Yeast Culture Experiments - Homebrew Horny Tank

In a 2007 NHC Presentation, Vinnie Cilurzo (of Russian River Brewing) suggested homebrewers try keeping a Horny Tank (inoculation tank) for maintaining mixed cultures. Used in many of the sour breweries in Belgium, he thought it may be a good way to keep a mixed culture viable without keeping a starter or brewing on a production schedule. A run-down of the process:

1. Start a normal batch of sour beer with a mixed culture.
2. Allow the beer to ferment in a plastic bucket for at least three months.
3. Any time after three months, brew another batch of wort.
4. Transfer the first batch to secondary for further conditioning, leaving behind a bit of liquid, the yeast slurry, and trub.
5. Immediately add fresh wort to the fermentor with the wild yeast slurry.
6. Repeat.

I started my own "Homebrew Horny Tank" last October. I brewed a blonde wort with a traditional turbid mash and inoculated the batch with several doses of revitalized, commercial bottle dregs. I plan to mature the beer in the bucket, tasting every few months.

The fear in using plastic buckets to condition a wild-fermented beer is that the bucket allows too much oxygen diffusion, resulting in excessive acetic acid production. After doing some research, it seems this fear is perpetuated by a single source. Although this article is an incredible resource for brewing sour beer, I believe the plastic bucket deserves a second chance.

To be safe, I will only disturb the beer to take samples, and I will purge the headspace with CO2 after sampling. When the beer is "ready", or if it displays the slightest amount of acetic acid, I will transfer it into a keg, leaving behind about a quart of beer, trub, and slurry. I'll then immediately transfer another batch of wort into the bucket and start the experiment over.


So far the results have been positive. Surprisingly, the bugs from the bottle dregs made quick work of the wort, completing primary fermentation in nine days and forming a pellicle in about two weeks. My first (and most recent) sample was three months after brewday (1/13). As expected, the beer tasted very young, with only a slight prickle of acidity. The aroma had a heavy sulfur note, which I believe will mellow with time (I've had sulfur aromas in a few other young sour brews). More importantly, the beer showed no signs of acetic acid production in the aroma or flavor. So far, so good.

In keeping with the theme of this blog, I want to find mixed culture methods that will translate well to a commercial scale. My mixed culture starter method could be utilized in a commercial brewery, but I believe it will often not be financially or logistically feasible. The brewery may not have the space or funds to allocate a fermentor or yeast propagation vessel specifically for wild yeast. At the same time, banking a special blend, or buying several strains of yeast and bacteria to produce a relatively small quantity of beer can also be extremely expensive.

In addition to those producing only sour and funky beers, I believe the horny tank technique could also work for commercial breweries producing them in limited amounts. Though still taking up fermentor space, it allows the brewer to consistently produce sour beer from the culture, rather than just store the slurry. The horny tank is flexible, allowing the brewery to keep a batch of fermenting sour beer and a viable culture in the same vessel. Though some may call this method sacrilege or assume its a shortcut, the time, resources, and money required to create a barrel-aged sour beer often makes them prohibitive. As homebrewers are creating fantastic funky and sour brews in glass, plastic, and stainless, I believe commercial brewers can do the same.

I will continue to make updates on this experiment as well as others in this series. To be honest - I don't see the series ending. I hope to continue playing with sour beermaking techniques, learning new techniques, finding new bugs, and creating new flavors. Let's face it - you can never have enough good sour beer around the house!

Wild Yeast Culture Experiments - Intro and Mixed Culture Method

Brewing (and drinking) sour, funky, "wild" beers is a passion of mine. I always have at least a few microbe-laden brews fermenting. I focus much of my reading and researching on topics surrounding sour beer. For me, brewing with brett and bacteria is a perfect combination of science and alchemy. I am basically the bugs' assistant brewer; preparing the equipment and materials so they can make the magic.

My most successful sour projects have all been fermented with a cocktail of flora, harvested from dregs of my favorite commercial sour beers. Maintaining and fermenting with this mixed culture has yielded significantly more depth and complexity than commercial  yeast/bacteria blends.

A double batch of Flanders Red, split and fermented with Wyeast Roselare (left) and my mixed wild culture (right). The mixed culture portion showed significantly higher levels of acidity and brett character.

I do not have the resources to plate and bank yeast, so I am limited to a macro-scale mixed culture. In the past, it has been as simple as a 1-gallon growler with 2-3 quarts of low gravity wort. The initial pitch is normally either a pack of commercial yeast blend or dregs from a few bottles of young, lower-gravity commercial sours. Prior to pitching the dregs into the starter, I will conduct a small step up with a few ounces of wort in the bottle. This gives the dregs a fighting chance in the mixed culture, and it is a decent test for both contamination and yeast health. The main culture is routinely decanted and fed fresh wort every 3 months or so.

My method is a primitive one, giving up even more control of the finished product to the yeast. However, I have been able to use the culture over a period of 2-3 years, all the while creating beers with strikingly similar  flavor profiles and levels of acidity and attenuation. The most significant differences stem from the additional depth contributed from introducing new species into the culture over time. I have yet to find the "expiration date" of a mixed culture; I have used all of the slurry before noticing any undesirable changes.

This series of posts aims to compare different methods of maintaining wild yeast cultures on a 'macro' level. More to come!

Wild Yeast Culture Experiments - Separating the Bugs

Over the past few months (or in one case, years), I have gathered commercial cultures of several yeasts and bacteria. The goal for this batch of microbes is to grow and maintain the individual cultures separately. I will use a fair amount of each culture in this year's lambic-esque brew, but I will also keep the individual cultures going for other experiments (berliner weisse and a brett-spiked saison, among others).

I love to collect sour beer dregs from commercial breweries, so I added a bit of the starter wort to a few freshly-consumed bottles. If these bottle cultures are successful, they will start off a fresh mixed culture.

Somewhat of a primer of what's to come, the cultures in this post are part of a set of experiments I started over a year ago. I am currently experimenting with several methods of maintaining mixed wild cultures, and hope to post results in the coming months!

Starter "Brewday": 01/08/13

Per Yeast text: 1g DME for every 10 mL H20

Made 8.5L starter with 850g of Briess Light Dry Malt Extract. Added 1/4 tsp Wyeast yeast nutrient.

Cooled to 80F. Poured into sanitized growlers and left on front porch until 65F.

Pitched following yeast (containers described, just in case labels fall off):


3.5L (1-gallon, clear growler) - 1056 starter
Note: this yeast is just for my next brewday

2L (Sun King growler) - Lacto starter

1L (traveling growler) - Brett Clausenii starter

1L (Flat12 growler) - Pedio starter

Note: As you can see from the picture, I got this Pedio starter for a bargain! I bought it last year, already out of date. The manufacture date on the package is March 2011 (Wyeast recommends using within 6 months), so I am not sure if this culture will yield any viable bugs.

1L (3WM growler) - Sherry Flor starter

~ 0.5L (from over-filled growler) - Split between two 750mL bottles