Wednesday, May 4, 2011

Autumn Maple II and the Yambic

Back in October of ’09 when we set out to clone the Bruery’s Autumn Maple, we were experimenting with a strain of yeast that we hadn’t worked with before…the Bruery’s house yeast.  With commercial strains, you can review the fermentation specs before hand and expect the yeast to maintain those same properties, allowing you to craft a beer to your own desires.  With unknown strains though, aside from scouring the internet to find another brewer who captured and brewed with the same strain, you’re basically left to assumptions and experimentation.  Those assumptions led us to brew a 13% abv beer when, in fact, we intended to only brew a 10% beer.

Although the 13% version of Autumn Maple turned out to be a fantastic beer in its own right, it wasn’t what we were aiming for and before settling on the recipe, we wanted to make some adjustments to hit our initially intended goal.  Two things come to mind: 1.) gravity/abv and 2.) flavor profile.

First the ABV.  With the ’09 batch of Autumn Maple, we made the assumption that the Bruery’s house strain of yeast would act in a similar manner to most commercially available, high-gravity Belgian strains of yeast and attenuate somewhere in the range of 74-78%.  With this assumption in mind, we crafted the beer to have an OG of 1.100 so that at 76% attenuation, we would end up with about 10% abv.  After fermentation completed, we discovered that the yeast could tear through the wort and was capable of attenuation rates closer to 98%.  With this knowledge in mind, for batch two we decided to scale down the OG to 1.080 so that at 98% attenuation, we’d end up with a 10% beer.

Second, the flavor.  A complaint that I often have with pumpkin beers is that you only taste the spices and not the pumpkin.  With our first batch of Autumn Maple, the spice mixture was at a perfect level and although there was a touch of yam flavor, it didn’t stand out as much as we wanted it to.  Whereas with the first batch we only added the cooked yams to the mash, for batch 2 we decided that not only would we increase the amount of yams in the mash but we’d also add some yams to the boil.  With the increased volume in the mash and the new addition in the boil, hopefully the yam flavor will shine through and elevate the beer to new levels.

Autumn Maple II / Yambic

Recipe Specifics
Batch Size (Gal): 6.0
Total Grain (Lbs): 13.5
Anticipated OG: 1.080
Anticipated SRM: 14
Anticipated IBUs: 23
Wort Boil Time: 90
Anticipated ABV: 10.0%

46.5% - 9.0 lbs Domestic 2-Row
20.7% - 4 lbs Munich Malt
26.1% - 5 lbs Cooked Yams
3.2% - 10 oz. Grade B Maple Syrup (added at secondary)
2.8% - ½ lb CaraMunich
0.6% - 2 oz. Dark Molasses

65 grams Libery (pellets, 3.0% AA) @ 60 minutes
1 ½ grams Allspice, freshly ground @ 2 minutes
¾ gram Cinnamon stick, broken into small pieces @ 2 minutes
¾ gram Nutmeg, freshly grated @ 2 minutes
1 Tahitian Vanilla Bean, split and seeded @ 2 minutes

Bruery house strain – cultured from a bottle of Orchard White

Water Profile and Additions
Charcoal filtered Seattle water
Mash Additions: 0.1 gram/gallon baking soda
Boil Additions: 1.2 g/g Calcium Chloride, 0.25 g/g Epsom Salt, 0.2 g/g table salt.

Mash Schedule
15 minutes @ 135°
60 minutes @ 151°
20 minutes @ 168°
Sparge with 170° Water


Brewed on 9/26/2010 with Blake and Paul

9/13/2010 – Started growing up the dregs from an Orchard White.  Same process was used as in the first batch: Harvested the dregs from a bottle of Orchard White and mixed with 10ml of 1.035 worth.  Once fermentation started, I added another 20ml and then 24 hours later, another 50ml.  24 hours after that, I stepped it up to 250 ml, then 1000ml, then 2000ml, and then 4000ml all with about 24 hours in between each step.

9/26/2010 – Placed about 5lbs of washed yams on the BBQ and 5lbs in the oven for about 45 minutes.  After the yams were cooked, we mashed them all up, skins and all and measured out 5lbs to add to the mash (shortly after dough in).

With the additional yam content, we ran into a few issues where the mash stopped recirculating.  We were able to get it started again each time by stirring the mash and back-pressuring the line.  Next time, we’ll add rice hulls.

Other than the few stuck mash times, the mash went smoothly and our efficiency was great.  Collected 7 gallons of 1.069 wort and topped off kettle to a little over 7 ½ gallons.

Hops added at 60 minutes.
Molasses added at 20 minutes.
Whirlflock and yeast nutrient added at 15 minutes.
Spices were added at 2 minutes.  Same amounts were used as during the first batch: 2 parts allspice, 1 part cinnamon, and 1 part nutmeg (3 grams in total).  We also added one whole Tahitian vanilla bean which we split and seeded.

90 minute boil.  Wort chilled to 68° and 60 seconds of pure 02 was dosed.  6 gallons of 1.081 wort in total.  5 gallons went into one carboy and then the Bruery yeast was pitched.

Yambic - About ¾ of a gallon of the pre-pitched wort went into a gallon jug.  To this jug, we added a ½ cup of a sour starter that we had on hand (starter contained the dregs from numerous beers: Deviation, Vagabond, Isabelle Proximus, Girardin Gueuze 1882, etc).  Should be interesting to see what it can do to such a high gravity wort.

Primary fermentation took place at 68°.

10/6/2010 – Racked to secondary and 10 oz. of grade B maple syrup were added.  Beer was moved up to my office which had an ambient temp of about 70°.

12/11/10 – Moved both the Yambic and the Autumn Maple down to the basement where temp is about 63°.  Gravity at 1.002.

3/6/2011 – Kegged the autumn maple.  There’s definitely more yam flavor than the first batch, but the beer is also more cloudy.  With the lower alcohol, it’s smoother than the first beer initially was but it also doesn’t taste as complex or rounded.  We’ll see what it’s like with carbonation.

11/17/2011 - Tasting and review


  1. Is 1 ½ grams Allspice, ¾ gram Cinnamon stick, and ¾ gram Nutmeg accurate? A paper clip is 1 gram, and to have less cinnamon than that seems negligible.

    1. Yup, those are definitely the correct amounts. I always grind up or grate the nutmeg and allspice and so the potency of them is a bit more than pre-ground spices. Also, with the highly attenuative yeast that was used, it really doesn't take much for the spice flavors to stand out.

  2. When did you add the yams to the boil?


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