Friday, April 15, 2011

Brettanomyces Experiment - Initial pH, Attenuation, and Secondary Metabolites

Over the years, I’ve found that new brewers typically fall into one of two categories:  those that like to jump in with both feet and learn from experimentation or those that like to research as much as possible before making the leap.  I certainly fall into the latter category and so as expected, when I started venturing into the world of wild fermentations, I scoured the seemingly limited, publicly available information.  

When I came across Chad Yakobson’s dissertation on brettanomyces, I was really intrigued.  In his “Brettanomyces Project”, one of the things that he examined was the effect that varying amounts of lactic acid concentrations have on attenuation as well as secondary metabolites.  Depending on the strain that he was studying, he basically found that, “higher initial concentrations of lactic acid had a significant effect, increasing the level of attenuation observed in each strain while generally decreasing the secondary metabolites produced” (Yakobson).  As a career analyst, the myriad of data fascinated me but as an intrigued homebrewer, I was left without a subjective view.  If the amount of ethyl lactate production is correlated with the initial lactic acid concentrations yet ethyl caproate is inversely correlated, what’s the initial lactic acid concentration that would give me the appropriate balance of flavors that I want in my beer?  What about attenuation?  Is the reduction in ethyl caprylate worth the increased attenuation?  As much as I value Yakobson’s numerical findings, these are the questions that I, as a homebrewer, want to find the answers to.

Even though I don’t have a home filled with sophisticated lab equipment, I wanted to try and replicate Yakobson’s experiment as best I could in order to determine my own subjective opinions.  The Brettanomyces Project dissertation examined the results of eight different strain profiles, but in order to keep things relatively simple, I decided to only work with two commercially available strains of brettanomyces lambicus:  Wyeast 5526 and White Labs 653.   

Even though I could have kept the grain bill of the base beer extremely simple in order to showcase the subtle nuances of the brett fermentation, I opted not to since most likely my future 100% brett beers will not have such a simple wort.  Since the point of this experiment is to find out what flavors I’ll want in future beers and the lactic acid concentrations necessary to arrive at such levels, I decided that using a base beer similar to what I’ll be brewing in the future will provide me with the most realistic results.  There’s no point in using a simple pilsner malt base if later I’ll be brewing with other specialty grains that could mask the very subtle flavors only apparent with a pilsner base.  In the end, I went with a grist of Maris Otter, Munich, Carahell, and Crystal 40.

Once the mash and boil were complete, I filled 12 one-quart mason jars with 28oz. each of clear wort.  These were then split into two groups of six, one soon to be inoculated with Wyeast 5526 and the other with White Labs 653.   In Yakobson’s study, he examined the fermentation at 5 different lactic acid concentrations.  Since I had six jars for each brett strain, I decided to replicate the lactic acid concentrations that Yakobson used plus one additional point.  After determining the g/L of lactic acid in the 88% solution that I had on hand, I was able to calculate the amount of acid needed to dose each 28oz mason jar to reach 0, 100, 500, 1000, 2000, and 3000 mg/L concentrations.

Concentration (mg/L)
ml of Lactic Acid Dosed
Initial pH

Unfortunately I don’t have access to equipment necessary to count the number of yeast cells per ml of wort, so when it came time to inoculate the jars, I tried to be as consistent with each as possible.  Four days before my actual brew date, I made a 600ml starter for each strain.  Since I only have one stir plate, I rotated between the two starters every 24 hours.  When it came time to pitch the yeast, I used a sterile syringe to suck up the yeast from each starter while it was still spinning on the stir plate so as to get a homogenous mixture for each test batch.  By dosing 15ml of homogenous starter to each jar, hopefully I ended up with roughly the same cell count in each batch. 

After fermentation resides in a few months, I plan to measure the final gravities and pH.  I should be able to be get two 12 oz. bottles out of each batch and soon after bottle conditioning, I’d like to hold one blind tasting with one bottle from each of the 12 experimental batches.  Hopefully the results will be obvious and conclusive, but if not, a second blind tasting after another year or so should provide another opportunity for critique.

Batch Specifics
Batch Size (Gal): 5.0
Total Grain (lbs): 9
Anticipated OG: 1.050
Anticipated SRM: 5
Anticipated IBU: 17
Wort Boil Time: 60 minutes
Anticipated ABV: Varies by initial pH / Lactic Acid concentration

89.2 % - 8.0 lbs Maris Otter
7.4% - 0.66 lb Munich Malt
1.7% - 2.5 oz. Carahell
1.7% - 2.5 oz. Crystal 40

60 minutes – 20 grams Cluster (Pellets, 5.0% AA)

Wyeast 5526 Brettanomyces Lambicus
White Labs 653 Brettanomyces Lambicus

Water Profile and Additions
Charcoal filtered Seattle water
Mash Additions: 0.65 g/g Calcium Chloride, 0.35 g/g Epsom Salt (based on 3 gallons)
Boil Additions: 0.65 g/g Calcium Chloride, 0.35 g/g Epsom Salt (based on 3 gallons), and 0.2g/g Salt (based on 6 gallons)
Lactic Acid – dosed into individual batches at rates mentioned above

Mash Schedule
60 minute rest at 152°
15 minute mash out rest at 168°
Sparged with 170° water

4/6/2011 – Started Wyeast 5523 starter (600ml) and placed on stirplate

4/7/2011 – Started White Labs 653 starter (600ml)…unfortunately it didn’t arrive the same day as the Wyeast.  Swapped Wyeast for White Labs on the stirplate.

4/8/2011 – Switched starters on the stirplate.

4/9/2011 – Switched Starters on the stirplate.

4/10/2011 – Brewed solo.

Hit strike 152 mash temp dead on.  Added mash mineral additions.

Collected 5 gallons of 1.060 wort.  Topped off to 7 gallons with filtered water, boiled for 60 minutes, and ended with 6 gallons of 1.050 wort.

Whirlflock and yeast nutrient were added at 15 minutes remaining.

Whirlpool chilled to 70° degrees and then let sit for about an hour and a half covered, waiting for the wort to completely settle.

Used kettle valve to fill 12 quart jars with 28 oz. of clear wort.

Remaining wort was used to fill another mason jar and a 1 gallon jug, both to be placed in various spots in my brewery to test out spontaneous fermentation.

For the 12 test batches, a 1ml syringe was used to dose each of the jars to the appropriate lactic acid concentrations (see grid above).  After lactic acid concentrations/pH levels were correct, 15 ml of brett were added…Wyeast to 6 jars, White Labs to 6.

Test batches were placed in closet where ambient temp is about 70°.

8/17/2011 - Bottled each sample

9/15/2011 - Blind Tasting Results

Pro-Am Imperial Red with Rye

Although it was a lot of fun in the beginning, I rarely submit our beers to competitions anymore.  There was a point when I felt like judges’ feedback was the only place where I could get honest, constructive criticism, but now, with a large group of obsessed beer nerd friends, my options have expanded and the opinions of the judges no longer seem to hold as much weight as they used to.  With the homebrewing world growing and more and more brewers interested in passing the BJCP exam and later judging, I also found it extremely frustrating when you received two contradictory judging scores and notes.  That said, there is still one competition that I like to enter each year…the Puget Sound Pro-Am.

Although the Pro-Am competition is initially judged according to BJCP guidelines, it differs from other competitions in that local breweries select beers of their choosing to be scaled up and brewed at their breweries.  They don’t always select the top beer in each category and often they’re only looking for beers of a certain style.  If they do end up selecting yours though, the commercially brewed version will most likely be submitted to the Pro-Am competition at the Great American Beer Festival in Denver.  

With the limited time and planning that we had, deciding on a brewing strategy for the competition was not a simple task.  Granted that we had some beers on hand that we could submit, we wanted to brew a few beers specifically for the competition that we believed could give us a leading edge.  

One thing that helped define a strategy for us was to look at what the trends were last year.  In years past, it seemed like whatever did well at the GABF would do well at the local Pro-Am the following year.  Two of last year’s winning GABF beers included rye and the 1st place beer was an imperial red ale with rye (Red Velvet).  Given that rye’s a unique enough ingredient to make a beer stand out, yet it’s still easy to work with and produces repeatable results (as opposed to spices or the like), it seemed like a good option to incorporate into a recipe.  About a year ago, we brewed an imperial red ale that, as far as all our hop-forward beers went, turned out to be one of my favorites that we’ve produced.  Incorporating rye into the recipe seemed only natural and when the recipe for Red Velvet was printed in the November issue of Zymurgy, it turned out that our own recipe was extremely similar (with the acception of the rye addition).

With a few modifications to our imperial red ale recipe, we essentially were killing two birds with one stone.  I guess only time will tell if it’s a smart move or not, but using a unique-enough ingredient like rye and mimicking a winning style from last year seemed like a strategy worth trying.

Holden's Red

Recipe Specifics
Batch Size (Gal): 6.0
Total Grain (lbs): 18.13
Anticipated OG: 1.087
Anticipated SRM: 17.3
Anticipated IBU: 90
Wort Boil Time: 90 minutes
Anticipated ABV: 9.5%

69.0% - 12.5 lbs Maris Otter
16.5% - 3.0 lbs Flaked Rye
5.5% - 1.0 lb Crystal 60
5.5% - 1.0 lb Munich Malt
2.1% - 6oz. Crystal 120
1.4% - ¼ lb Pale Chocolate

75 minutes – 40 grams Magnum (Pellets, 12.1% AA)
30 minutes – 30 grams Simcoe (Pellets, 11.5% AA)
10 minutes – 25 grams Amarillo (Pellets, 7.1% AA)
0 minutes – 40 grams Centennial (Pellets, 8.5% AA)
0 minutes – 20 grams Cascade (Pellets, 5.6% AA)
0 minutes – 15 grams Amarillo (Pellets, 7.1% AA)
Dry – 40 grams Amarillo
Dry – 40 grams Cascade
Dry – 40 grams Centennial

Wyeast 1056 American Ale (1500ml starter)

Water Profile and Additions
Charcoal filtered Seattle Water
Mash Additions: ½ gram per gallon Chalk, ½ g/g baking soda.
Fermentation Addition (see notes): 6 grams gypsum, 2.4 grams Epsom salt, 3 grams table salt.

Mash Schedule
60 minute rest at 152°
15 minute mash out rest at 168°
Sparged with 170° water

3/4/2011 – Made 1 liter starter of 1.035 wort.

3/5/2011 – Added 500 ml to starter.

Brewed 3/6/2011 with Blake.

Doughed in at 158° and hit our 152° mash temp dead on.  Added mash mineral additions and hit 5.2 pH.   

Rested for 60 minutes and then sparged until we had 7.5 gallons in the kettle with a total of 638GUs.

Boiled for 90 minutes and with 15 minutes left, we added whirlflock and Wyeast yeast nutrient.

Chilled down to 66° and racked beer into carboy.  Started to oxygenate with tank 02 and airstone, but our tank was low so we only got about 10 seconds of 02 in there.  After realizing this, we shook the crap out of the carboy for another 5 minutes.

Started fermentation at 66°.

3/7/2011 - Realized we didn’t add the boil kettle mineral additions, so we boiled up a cup of water and added the minerals that we would have added into the kettle.  Water was cooled and then dumped into fermentor. 

3/10/2011 – Raised temp to 68°

3/22/2011 – Needed the space in the fermentation chamber, so I brought the carboy up to my office.  Ambient temp, ~70°.

3/23/2011 – Added dry hop additions to primary.

3/30/2011 – Wanted to get the beer off the dry hops, but since the beer was still very slowly fermenting, I transferred the beer to a C02 flushed carboy instead of kegging.

4/8/2011 – Crash cooled beer in basement fridge.  FG: 1.017

4/10/2011 – Kegged and carbonated to 2.6 volumes.

Tasting Review

Monday, April 11, 2011

Bourbon Wood-Aged Tripel

Every beer geek can probably remember back to the first craft beer they had that opened their eyes to the vast array of flavors that can be present in a beer.  For me, that beer was Chimay Grande Reserve.  Unlike anything I had ever had before, it drove my curiosity to explore other Belgian styles and before I knew it, Tripels became my new favorite.  To this day, I still love how the spiciness from the yeast and alcohol plays well on top of the soft malt character while the high carbonation helps to aid in a dry, slightly bitter finish.

As a homebrewer, brewing a Tripel isn’t the most exciting beer in the world to make.  Granted that it can be difficult to achieve the dryness and the right characteristics from the yeast without producing an overly hot beer, a grain bill comprised of mainly pilsner malt and cane sugar just doesn’t hold the same appeal that maybe a barleywine does.  To up the ante a little bit, I wanted to add another layer of complexity by incorporating the flavors that a beer often receives during extended aging in a bourbon barrel.

Before getting too excited about the simulated bourbon barrel aging, I wanted to make sure that the base beer wasn’t neglected and that it still retained the properties of a high quality Tripel.  To me, a lack of dryness and excessive alcohol heat are two of the most common flaws in this homebrewed style and so to combat this, I wanted to make sure that the base beer had plenty of easily fermentable sugars and that the fermentation temps were restrained.  The grist of primarily German pilsner malt was mashed long and low at a temp of 147° and then to the boil, nearly 18% of the total fermentables were added in the form of cane and candi sugar (it would have been fine with 100% cane sugar, but since I had a 1lb bag of clear candi syrup on hand, I decided to throw it in).  As for the fermentation, I pitched a 1500ml starter of Wyeast’s Trappist High Gravity yeast to the wort at 64°.  Even though this strain of yeast can handle much higher temps, I decided to keep it low initially to restrain the heat and excessive phenolics.  After a period of 36 hours, the temp was raised 1° per 24 hours until a max temp of 72° was reached to finish out the beer.

After primary fermentation, I started the simulated bourbon barrel aging process.  The beer was racked into a keg which contained 1 oak stave that had been soaking in Makers Mark for about 2 weeks.  I knew that this would not be quite enough oak or bourbon to impart the desired flavors, but I wanted to take it slow.  Part of my problem with other Bourbon Aged Tripels is that the bourbon is too forward and the subtleties of the base beer are lost.  I wanted this beer to be a quality Tripel first, with just a hint of bourbon and oak on the finish.  After three months, you really couldn’t perceive any bourbon or oak character, so I added two more oak staves and an 8th of a cup of bourbon.  With another two weeks passing, the bourbon still wasn’t quite where I was aiming.  After letting the beer rest for one more week, I pulled out a glass and using a 1ml dosing syringe, I continued to add more bourbon until the appropriate balance was reached.  Scaling this amount up for the volume that I had in the keg, I ended up adding another 12mls.  

Bourbon and Oak aged Tripel

Recipe Specifics

Batch Size (Gal): 5.5
Total Grain(lbs): 10 ¼
Anticipated OG: 1.070
Anticipated SRM: 4.5
Anticipated IBU: 32.0
Wort Boil Time: 90 minutes
Anticipated AVB: 9%

78.4% - 10.0 lbs German Pilsner
11.8% - 1.5 lbs cane sugar
7.8% - Clear Candi Syrup
1.5% - 3 oz. Aromatic Malt
0.5% - 1 oz. Biscuit Malt

60 minutes – 40 grams Styrian Goldings (Pellets, 5.2% AA)
10 minutes – 20 grams Czech Saaz (Pellets, 5.5% AA)

Wyeast 3787 Trappist High Gravity (1500ml Starter)

Water Profile and Additions

Charcoal filtered Seattle Water

Mash Additions: 1 gram/gallon Calcium Chloride, ¼ gram/gallon Epsom Salt, 0.085 gram/gallon Baking Soda, and 0.2 gram/gallon Salt.

Sparge Additions: 1.3 gram/gallon Calcium Chloride

Mash Schedule
60 minute rest at 147°
15 minute mash out rest at 168°
Sparged with 170° water

10/28/2010 – made starter with 1 liter of 1.35 wort.

10/29/101 – added 500ml of wort to starter.

Brewed 10/30/2010 – solo.

Hit dough-in temp of 147 exactly and rested for 60 minutes.

Whirlflock and yeast nutrient added with 15 minutes to go in the boil.

Chilled down to 64°.  Ended with 6 gallons of 1.070 wort.  Aerated for 60 seconds with pure 02 and pitched yeast starter. After 36 hours, temp was raised 1 degree per day until 72° was reached.

12/11/2010 – Transferred to secondary.  Added 1 oak stave (1 inch by 1 ½ inch by ¼ inch) that had been boiled for 10 minutes and then soaked in Makers Mark for 12 days.  Secondary was moved down to the basement which was about 63°.  Gravity down to 1.005.

3/6/2011 – Bourbon and oak are extremely subtle…almost non-existent.  Added two more oak staves (both had been boiled) and about 1/8 cup of Makers.  Moved to fridge to lager.

3/11/2011 – Added 1 more oak stave.

3/29/2011 – Taste wasn’t exactly where I wanted it, but I started carbonating to 2.4 volumes anyway knowing I would add more bourbon later.

4/10/2011 – Using an 8oz sample, I gradually dosed bourbon until the right balance was reached.  After scaling this up to the full batch, I ended up adding another 12mls to the keg.
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