Wheat yeast comparison experimental design

Time for another experiment. After brewing some wheat beers I asked myself, what could do a different yeast to a wheat beer flavor-wise. To determine the impact of different yeasts I started a little experiment. I will post the results in a separate post as this experimental design description is quite long.

Aim of the project

The goal of this project was to determine the flavor impact of different wheat yeast strains. Further on, has the dry yeast WB-06 similar/the same flavors as the Wyeast #3068 Weihenstephan? (some people suggest that WB-06 is the same strain as Wyeast use for their #3068)

Background

Yeast information

To get an idea of the flavor profile of the used wheat strains, it is inevitable to research for some information about the yeast strains. The following information are from the yeast suppliers Wyeast, Danstar and Fermentis:

#3068 Weihenstephan: 73- 77% (18- 24°C) (64- 75°F)
Banana ester, phenols and clove-like characteristics. Alcohol Tolerance: 10% ABV (alcohol by volume), low flocculation.

#3056 Bavarian Wheat Blend: 73- 77% (18- 23°C) (64- 73°F)
Blend of top-fermenting ale an wheat strains producing mildly estery and phenolic wheat beers. Alcohol Tolerance: 10% ABV, medium flocculation.

#3333 German Wheat: 73- 76% (17- 24°C) (63- 75°F)
Unique sharp tart crispness, fruity, sherry-like palate. Alcohol Tolerance: 10% ABV, high flocculation. Banana and clove. It seems that Wyeast changed their homepage since I planned my experiment.

#3638 Bavarian Wheat: 70- 76% (18- 24°C) (64- 75°F)
Complex flavor and aroma. Balance of banana and bubble gum esters with litchi and apple/plum esters and clove. Alcohol Tolerance: 10% ABV, low flocculation.

#1010 American Wheat: 74- 78% (14- 23°C) (57- 73°F)
Dry fermenting, slightly tart, crisp beer. Ideal for beers where low ester profile is desirable. Alcohol Tolerance: 10% ABV, low flocculation.

#3942 Belgian Wheat: 72- 76% (18-23°C) (64- 73°F)
Moderate esters and minimal phenolic. Apple, bubblegum and plum-like aromas blend nicely with malt and hops. This strain will finish dry with a hint of tartness. Alcohol tolerance: 12% ABV, medium flocculation.

Coopers Wheat: (19- 21°C) (66- 70°F)
Isolated from a Coppers Wheat kit. It might be no real wheat yeast.

Dry yeast Fermentis Safbrew WB-06: (15- 24°C) (59- 75°F)
Subtle ester and phenol flavor notes. Low sedimentation. Final gravity: high.

Dry yeast Danstar Munich: (> 17°C) (> 63°F)
Medium to high attenuation, non flocculent strain, esters to both palate and nose with typical banana notes.

Burgdorfer Weizenbierhefe
Isolated from a local wheat beer (Weizen, Burgdorfer Gasthausbrauerei)

Wheat beer profile

BJCP: 15A Weizen/Weissbier, OG: 1.044-1.052, FG: 1.010-1.014, IBU: 8-15, SRM: 2-8, ABV: 4.3- 5.6%.
Methods: Resting at 44°C (111°F) enhances the 4-vinylguajacol production (precursor for the wheat typical clove aroma). Typical pitching rates for wheat beers: 5- 10 E6 cells mL-1.

Hypothesis

Banana Phenolic Clove Ester Cloudy Notes
#3068 Weihenstephan X X X X Typical wheat aromas
#3056 Bavarian Blend X X No banana
#3333 German Wheat X X X No banana
#3638 Bavarian Wheat X X X
#1010 American Wheat X No typical European wheat aromas
3942 Belgian Wheat X X Fruity character, light phenolic notes
WB-06 X X X No banana, phenolic
Danstar Munich X X X Typical wheat yeast, comparable to #3638
Burgdorfer Weizen No idea

Experimental design

Recipe: Wheat experiment
Numbers: Volume 20 L (5.3 gal)
Original gravity 13.5°P
Terminal gravity 3.5 – 4.2°P (yeast dependent)
Color Around 4 EBC
IBU 13 IBU
ABV Around 5.3 %
Grains: Pilsner malt (3 EBC) 2.1 kg
Wheatmalt (3 EBC) 2.6 kg
Acidified malt (5 EBC) 0.1 kg (see rest)
Hops: Hallertauer (4.2% AA) 11.4 g and boil for 60 min11.4 g and boil for 30 min
Yeast: See above
Water: Burgdorf Mash: 12 L (3.2 gal), lauter: 19 L @78°C (174°F) (5 gal)
Rest: 4 steps Mash in @47°C, 20 min @ 45°C (113°F), 15 min @53°C (128°F)(add acidified malt), 30 min @63°C (145°F), 40 min @72°C (162°F), mash out @ 78°C
Boil: Total 60 min
Fermentation: Primary See below
Secondary In bottle
Maturation: Carbonation (CO2 vol) 2 vol for bottles
Maturation time 3 Weeks @18°C (64°F)

Fermentation

Used for each yeast two times 2 L (0.5 gal) of wort. Inoculated the yeasts at 12-15°C (54- 59°F) and primary fermentation at 18- 22°C (64- 72°F) till final gravity reached (one week). Pitching rate: 5 E6 cells mL-1. Secondary fermentation in bottles for one week at 20°C (68°F). Maturation at 4°C (39°F) for three weeks.

To ferment ten batches simultaneously I had to use small buckets. They have a volume of about 2.5 Liters (0.66 gal).

Fermentation vessels for the wheat yeast experiment

Yeast ranching

As I had some strains in my library, I had to cultivate some strains from my library and some from Propagators from Wyeast. The strains from my library: Inoculated yeasts to 200 mL (0.05 gal) of 10°P sterile wort (20 g of dried malt extract to 200 mL tap water) and let them ferment on my stirrer. I propagated the #3068, #3056, Coopers Wheat and Burgdorfer Weizen as previously mentioned.
For the Propagator I used 20 mL of the volume of the packages. And for the dry yeasts: 1.25 g of WB-06 to 2 liters, and 2.5 g of Danstar Munich to 2 liters (0.5 gal) of wort.
I determined the cell densities of all the starters (expect the Propagators) by use of a Neubauer cell count device to ensure the right pitching rates.

Yeast plan

Three batches (3 times 20 L (5 gal)) were made to supply enough wort for the experiment:

1. Batch (20 Liters) for #3068 Weihenstephan (reference), WB-06, #1010 American Wheat, #3333 German Wheat and Coopers.
2. Batch (20 Liters) for #3068 Weihenstephan (reference), #3056 Bavarian Wheat Blend, Burgdorfer Weizen, #3638 Bavarian Wheat.
3. Batch (40 Liters) for #3068 Weihenstephan (reference), #3942 Belgian Wheat. The rest of the volume was used for a different beer and had nothing to do with this experiment.

The reference strain (#3068 Weihenstephan) was used to ensure the comparability of the three batches. Each yeast was inoculated to two different worts as a repeat.

Tasting

Determine the differences between the repeats of the same yeast. Then determine differences between the batches with the reference strain. Determine differences between the WB-06 strain and the #3068 Weihenstephan strain. Define flavor profiles of the different yeasts. Which is the most appropriate strain to use in a wheat beer according to the tasting panels opinion?

Results and Discussion

Will be published in a post in the near future as I am still working on the data analysis.

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6 thoughts on “Wheat yeast comparison experimental design

  1. Oh that’s a nice experiment. Keep it up. I’d sure be interested to see your results.
    Just one question – do you think 5 E6 mL-1 is enough or are you aiming for increased ester/phenol production?
    Cheers!
    Dmitri

    • Hi Dmitri,
      Well I got my numbers from the following presentation: http://www.mbaa.com/Districts/MidSouth/presentations/Wheat_Beer_Yeast__Fermentation2.pdf
      On slide 34 is an overview about the brewing process of the Schneider brewery in Germany. I more or less took over the numbers. On slide number 20 is an overview and it seems that many breweries in Germany use this pitching rate. And thats why I used this pitching rate. The beers seemed fine so far. Thanks for following. I am still processing all the numbers and tasting notes to get to a final conclusion of the whole experiment.
      Cheers
      Samuel

      • Wow! That’s a really informative wheat beer presentation. Thanks a lot!
        The reason I asked is that here people seem to aim for 10 E6 mL-1 for ales so far as I know. Maybe 5E6 is good for wheats to increase the flavors?

        • Yes you are right. For a normal ale you would pitch in the range of 10 E6 mL-1 (pitching rate = 0.75 E6 * OG [°P]* Volume [mL]). And for wheat beers, I experienced that decreasing the pitching rate to about 5 E6 mL-1 seems to increase the flavors (as mentioned in the presentation). But there are other sources where its mentioned to pitch in the range of 10 to 15 E6 cells mL-1. But there is the fermentation temperature as well which can influence the flavor profile as well. To summarize, it seems that the kind of yeast, the pitching rate and the fermentation temperature as well as the geometry of the fermentation vessel can influence the flavors and aromas of a wheat beer. That would be an interesting experiment as well to determine those effects.

  2. In winemaking, fermentation temperature is a key parameter for the wine aromatic profile. White wines are usually fermenting at 20C aprox. Lowering temperature to 13C is an good way to increase fruity aromas to the final white wine.
    As a suggestion, It could be interesting for your brewing research to check how the aromatic profile of the beer changes when the same yeast strain is fermenting at different temperatures.

    • Interesting. In brewing, lowering the temperature is connected to less fruity aroma as the yeast’s metabolism is slowed down. Testing different temperature profiles would be interesting indeed. But it is very unlikely for me to make another wheat yeast test in the future. Simply because my favourite wheat yeast strains, before and after this experiment, is still the same.

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