Sunday, 3 August 2014

Brew Day: Oud Bruin with Wyeast 3209

Tart Cherries for PreservesDespite having lots of other projects planned for the summer, I couldn't pass up the chance to try the seasonal releases from Wyeast, all of which are intended for making sour beers.  I didn't feel like taking a risk on the De Bom blend, but ever since I read some old posts by Al Buck of East Coast Yeast on BBB in which he talked about brewing an Oud Bruin with just saccharomyces and lactobacillus, I've been thinking about doing a Sour Brown Ale in this way.  The ECY blend seems to have been discontinued, but this Wyeast blend is based on the same ideas: lactobacillus to do the souring, sacchromyces to take care of the rest of primary fermentation, and no brettanomyces or pediococcus to munch through all the dextrins and take away any malty sweetness. (Update: Apparently I was wrong about this blend: it does contain brettanomyces. Jess Caudill from Wyeast has confirmed that there is no brettanomyces in this blend.)

Once I had the blend in my hand (a pack that was less than a week old, thanks to Rite Brew's pre-order system), I started wondering exactly how to use it.  For instance, the description on Wyeast's website states that fermentation should take place between 80-85°F.  This is a great temperature for lactobacillus, but how would the yeast perform if I pitched that high?  In the past, I've had undesirable results from pitching above 70°F, so I was reluctant to do it again.  Perhaps I could follow my normal procedure, pitching at a lower temp and letting it ramp up into these desired range?

Rather than simply guess, I decided to shoot a quick email to Wyeast; Jess Caudill got back to me with some helpful information about the blend, which I'll summarize below:

  • keeps the IBUs below 15; the l.brevis is more hop tolerant than other strains, but will still be inhibited by higher rates of hopping.
  • don't oxygenate at pitching; this will give the bacteria a head start.
  • pitch between 80-85; this will again let the lactobacillus thrive before the sacchromyces ferments all the available sugars; pitching at a lower temperature will result in a less sour beer.
  • the blend is designed to produce a drinkable beer in 6-8 weeks; oak accordingly.
I was still a bit worried about what the yeast would do if pitched at such a high temperature, but Jess assured me that they had selected a strain would still be quite clean in this range.

The blurb on the website also mentioned that this blend would provide an excellent base for blending with fruit in secondary.  At about the time I was brewing this beer, the local farmer's market had lots of tart and sweet cherries from Klug farms.  One rainy Saturday in early July I split a large box with a friend (she doesn't brew, but we both wanted to make cherry preserves as well), and froze what I had left in vacuum sealed bags.

For the brew itself, I decided to use Jamil Zainasheff's Oud Bruin recipe from Brewing Classic Styles.  The day went quite smoothly (although I missed by gravity by several points, a pattern I'm noticing on these higher gravity beers). In the end I elected to pitch in the mid-70s and let the beer free-rise into the 80s (which probably happened early in fermentation given the temperatures in my brew closet); I reasoned that I was going to add cherries anyway, which would increase the acidity, so there was less reason to maximize it from the start.

Today, about 2 and half weeks after pitching, I transferred the beer onto a 5-6 lb blend of tart and sweet cherries (remember, I do 3 gallon batches, so this is about 2lbs/gallon).  I had a fair bit left over, which I transferred to jugs with the intention of using it to dose some other beers (like the Keeping Porter I brewed last week) with the lactobacillus brevis.

The beer was only at 1.019 (down from 1.062), with a pH of 3.81.  It tasted fairly sour, with some fruity sweetness behind it; fairly rough around the edges, which is unsurprising given how young it is. Since I haven't been tracking fermentation, I have no idea if its stuck or if its just slowed down.  It wouldn't surprise me if the yeast gave up because of the acidity and alcohol; perhaps the lactobacillus will continue to slowly lower the gravity, but I suspect it will also be inhibited by the rising alcohol levels.  This, presumably, is how the blend can produce a drinkable beer in 6-8 weeks.  My only concern is that since I didn't take any steps to treat the cherries beyond freezing and defrosting them, adding them might inoculate the beer with a wild yeast strain that will prolong fermentation.

As I transferred the beer onto the cherries I had second thoughts about adding them so early.  Usually I'd wait many months before adding fruit (in fact, at the same time as transferring this beer, I added 3lbs of peaches to the golden sour I brewed a few months ago).  My original thought was that since the blend was supposed to be done in two months anyway, there would be no harm in adding the cherries early as I transferred to secondary.  In fact, since there was no brettanomyces in the beer to take care of oxidation, it made sense to minimize the number of transfers by adding the cherries at this point.

I'll check on the beer again in two months or so, and that will give me a sense of whether I made the right call.  If the gravity is about the same after the cherries have been fermented out, I'll feel fine bottling it.  If its continued to drop, I'll be worried that primary fermentation was incomplete when I added them, or that the beer has picked up some brettanomyces from the fruit.  In that case I'll just have to let it sit for longer.

26/11/14: Tasting Notes.

2 comments:

  1. How did the Oud Bruin turn out in this short time frame?

    I am used to seeing Oud Bruins age for 6 months to a year before they sour / blend together.

    How has the fruit flavor changed in these last two months?

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  2. I haven't got round to bottling this yet---should do this weekend. Last time I checked, the gravity had continued to drop and the beer was sour but otherwise a bit one dimensional. I'll post another update in a few weeks once its bottled and carbonated.

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