Hello, my name is Torulaspora delbrueckii

Eureka, we are back to science. Today, I would like to start with a series of posts covering various spoilage yeasts. The yeast of today is widely used in food production such as bread and bakery products but has a connection to beer as well. The yeast I am talking about is called Torulaspora delbrueckii. I stumbled upon T. delbrueckii a while ago as this yeast is apparently used in the production in Bavarian Wheat beers. However, I could not find any scientific reference discussing the use of Torulaspora in beer. The only published cases of T. delbrueckii in beer cover T. delbrueckii as spoilage organism.

Where do I work?

In general, all non-Saccharomyces yeasts are considered as spoilage yeasts associated with negative traits such as introducing off-flavors, impact on clarity and different sugar preferences leading to different attenuation levels (degree of fermentation). This is now changing and lots of efforts and research is put into examining the effects of different “spoilage” yeasts in either single inoculation or in mixed fermentations along with Saccharomyces cerevisiae, the working horse of most of the beer brewers, wine makers, spirit producers and lets not forget the bakers. One other “spoilage yeast” which gets a lot of attention lately is Brettanomyces for example.

The first positive effects of Torulaspora in mixed fermentations has been initially studied in wine where the use of Torulaspora increases the complexity of the final wines [Tataridis P, van Breda V, 2013]. And yeast products with this yeast are already available.

What about beer?

The first published evidence that Torulaspora has positive effects in beer was published by Tataridis et al in 2013. The authors fermented 3.5 L of malt extract wort (OG 1.044) each with WB-06 and a strain of Torulaspora delbrueckii and compared the beers. They first noticed that T. delbrueckii was capable of metabolizing maltose the most abundant sugar in wort. However, the fermentation using T. delbrueckii took a while longer to reach terminal gravity compared to the WB-06 fermentation (157 h vs 204 h). The beer fermented with T. delbrueckii was more hazy and had a higher terminal gravity (1.012 vs 1.009). Despite the higher terminal gravity and a slower fermentation activity, the most interesting differences could be observed in the final beers. T. delbrueckii showed higher ester notes (mainly banana, rose and bubblegum) and a decreased phenolic character than WB-06. Demonstrating that T. delbrueckii might have a potential positive role in the production of wheat beers.

Now that we covered some basics about the possible advantages of the yeast, lets look at the taxonomy and biochemistry.

A quick taxonomy journey

Questions to be addressed in this chapter are:

  1. What is the closest relative yeast of T. delbrueckii?
  2. How closely related are Saccharomyces cerevisiae and Dekkera bruxellensis (aka Brettanomyces bruxellensis) to T. delbrueckii?

To address these questions, one can look at certain DNA sequences of the different yeasts and compare them in terms of how similar they are. I will try to make this very simple here. Think of a mother yeast cell from which all existing yeasts originate and evolved during time. Kind of the ur-mother-yeast-cell. Lets assign the letter A to the mother yeast cell and B to be a yeast daughter cell of A. Let me walk you through some possible examples of B and its impact on the DNA compared to A. Please notice that this is a simplified version and I am fully aware that biology is a bit more complicated than depicted in this example.

  • B is a direct ancestor of A. B is a daughter cell of A and originates from a budding/fission event of A directly creating B. In this example, the DNA of both cells are the same (I intentionally leave mutations etc aside here)
  • B is an ancestor of A but not a direct one and evolved during time thereby changing the DNA sequences in B compared to A. B is still in the lineage of A but not very close any more due to evolutionary events. There can be several billion, billion, billion daughter cells between A and B. In general, more similar DNA sequences are more likely to be closer related
  • If B is very distant of A (in terms of DNA similarities), B is classified as separate species than A. In this case, B and A cannot interbreed any more because they are too distant of each others. S. cerevisiae and Dekkera for example would be daughter cells of A but very distant and form their own species

Lets take another example, horses. Zebra, horses and donkeys look very alike but are different species. (I intentionally leave mules aside here as this these animals are hybrids of horse and donkeys). It is very likely that all these species originate from some kind of ur-horse but individually adapted to new environments forming three different, new animals. To investigate which animal is closer related to which one, one could isolate DNA from the three animals and compare them.

To address what the relationship between T. delbrueckii and S. cerevisiae and Dekkera is, one can look at the large subunit of the ribosome (LSU rRNA). The ribosome is a complex of various subunits and is responsible for the protein synthesis in the cell. Because the ribosome is a very important machinery in a cell, the changes over time on the DNA level which encode parts of the ribosome are rather low. And can therefore be used to assess relationships among different species and strains. For T. delbrueckii, the relationship between some other yeasts is depicted in Fig 1 as a phylogeny tree. The tree begins with a common ancestor and the branches represent different fates.

Phylo_tree_torulaspora

Fig 1: Phylogeny tree of Torulaspora relatives based on LSU rRNA created using Phylogeny.fr

I included additional members from the Torulaspora genus to have some close relatives of T. delbrueckii in the tree. And Saccharomyces and Dekkera to see how they end up in the phylogeny tree. One can observe that S. cerevisiae seems to be closer to Torulaspora than Dekkera.

Addressing the closest yeast relative of Torulaspora delbrueckii is a bit more complicated. First of all, it all depends on the data one uses to construct the phylogeny trees. If you for example do not include the true closest yeast relative in the dataset you will not pick it up anyway. Looking through some published phylogeny trees makes it hard to give a final answer. In one example published by Kurtzman et al (2011), the closest relative of T. delbrueckii is S. cerevisiae (like shown in Fig 1). On the other hand, another phylogeny tree published by Kurtzman et al (2011) ends up grouping Zygotorulaspora and Zygosaccharomyces closer to Torulaspora than the Saccharomyces group. In the latter case, Zygosaccharomyces mrakii and Z. rouxii end up being the closest relatives. It is therefore not possible to give a final answer here based on my investigations. However, what is obvious from the phylogeny tree shown in Fig 1, Dekkera is farther apart from Torulaspora than Saccharomyces.

Torulaspora delbrueckii has a very long list of synonyms which include a lot of different genera like Saccharomyces, Debaryomyces, Zygosaccharomyces and Torulaspora. In 1970, Kurtzman et al assigned Torulaspora and Zygosaccharomyces to Saccharomyces leaving Debaryomyces as a separate species. Five years later, van der Walt and Johannsen recreated the genus Torulaspora and incorporated all Debaryomyces species to it as well. Nine years later, Kurtzman et al accepted all four species again. This is actually not very uncommon in yeast taxonomy which is why yeast taxonomy can be very confusing and undergo lots of changes.

One reason why Saccharomyces, Debaryomyces, Zygosaccharomyces and Torulaspora make the lives of taxonomists so hard is their biochemical and phenotypical similarities and behaviour. Thus making it hard to differentiate the species. In addition, different yeasts were initially assigned to species based on morphology and biochemical properties. Nowadays, yeasts are assigned to species based on DNA. Which can lead to a lot of taxonomical changes and re-assignments of various yeasts. That’s how it is.

Beside T. delbrueckii, five other Torulaspora species exist being T. globosa, T. franciscae, T. globosa, T. maleeae, T. microellipsoides and T. pretoriensis. All other species with the exception of T. microellipsoides and T. delbrueckii are not associated with beverages. T. microellipsoides could be isolated from apple juice, tea-beer and lemonade and is a contaminant of soft drinks [Kutzman et al, 2011].

Where can you find me?

Most of the Torulaspora species and strains are isolated from soil, fermenting grapes (wine), berries, agave juice, tea-beer, apple juice, leaf of mangrove tree, moss, lemonade and tree barks [Kutzman et al, 2011]. With a bit of luck, you may find yourself some Torulaspora or you may go with the available Torulaspora delbrueckii yeast products.

Some say that Wyeast’s WY3068 Weihenstephan is a Torulaspora delbrueckii strain or contains Torulaspora delbrueckii. At least based on micrographs, its hard to tell whether WY3068 Weihenstephan is different from a typical Ale yeast (such as WY1056 American Ale) (Fig 2, 3). If anyone has rRNA seqs from WY3068, please let me know.

WY3068

Fig 2: Wyeast 3068 Weihenstephan

WY1056

Fig 3: Wyeast 1056 American Ale

Some biochemical stats about me for yeast ranchers

Below a summary of the biochemical properties of T. delbrueckii. Data is summarized from Kutzman et al (2011). One way of differentiating between S. cerevisiae and T. delbrueckii can be performed using RFLP using HinfI on amplified ITS1-5.8S-ITS2 amplicons [van Breda, 2013]. Or obviously by sequencing the ITS1-5.8S-ITS2 amplicons.

Systematic name: Torulaspora delbrueckii
Synonyms: There are a lots of accepted synonyms for this yeasts. Just some examples: Saccharomyces delbrueckii, S. rosei, S. fermentati, S. torulosus, S. chevalieri, S. vafer, S. saitoanus, S. florenzani
Growth in malt extract: Cell morphology: Spherical, ellipsoidal, 2-6 µm x 6.6 µm
Clustering: Occurring as single cells or in pairs
Pseudohyphae: None
Pellicle formation: None
Growth in malt extract: Colony morphology: After 3 days: Butyrous, dull to glistening, and tannish-white in color
Fermentation: Glucose: Positive
Galactose: Variable
Sucrose: Variable
Maltose: Variable
Lactose: Negativ
Raffinose: Variable
Trehalose: Variable

That’s all about Torulaspora delbrueckii so far. I hope this was in a way informative to you. At least keep in mind that spoilage yeasts do not inevitably have to be bad. If one can use their potential for our advantage, we can make something really unique. Have fun playing around with Torulaspora delbrueckii.

Bibliography

  • Kurtzman CP, Fell JW, Boekhout T (2011) The Yeasts, a Taxonomic Study. Volume 1. Fifth edition. Elsevier (Link to sciencedirect)
  • Tataridis P, Kanelis A, Logotetis S, Nerancis E (2013) Use of non-saccharomyces Torulaspora delbrueckii yeast strains in winemaking and brewing. Zbornik Matice srpske za prirodne nauke, Vol 124, 415-426
  • van Breda V., Jolly N, van Wyk J (2013) Characterisation of commercial and natural Torulaspora delbrueckii wine yeast strains. International Journal of Food Microbiology, 163, 80-88

#82 Nelson Sauvined Berliner Weisse

Eureka, it’s time for another recipe. I would like to apologize for the few posts lately. I am currently in the last months of my Master’s degree and try to get as much out of my lab and grid time before sitting down and writing up my thesis (and a publication). I hope to find more time to brew and write afterwards. Back to the recipe, another Berliner Weisse recipe. I did two (more or less traditional) Berliner Weisse before and let the mash turn sour by adding some grains in one case (#44 Berliner Weisse) and one where I used Wyeast’s 3191 Berliner Weisse blend (#61 Berliner Weisse 2) without sour mashing. Comparing the two batches, the one with the sour mash turned out way better than the second one. I even did a dark Berliner in the meantime (using a sourmash) which turned out pretty well. I will therefore never, ever skip the sour mashing step again. And adding Brettanomyces is another must have as well. This recipe is actually more or less the same in terms of grist composition and the process as my very first Berliner Weisse. The only difference here is the dry hopping step with Nelson Sauvin. A dry hopped Berliner Weisse. Lets find out how good hops actually work in sour beers.

Recipe: Nelson Sauvined Berliner Weisse
Numbers: Volume [L] 20 (5.3 gal)
Original gravity 8.5°P (1.033)
Terminal gravity 1.7°P (1.006)
Color Around 4 EBC
IBU N/A
ABV 3.6% (v/v)
Grains: Pilsner malt (4 EBC) 1.9 kg
Wheat malt (4 EBC) 1.4 kg
Hops: Nelson Sauvin (12.3% AA) 12 g and added at mash in (mash hops)
Nelson Sauvin (12.3% AA) Twice 75 g for dry hopping
Yeast: Wyeast #1056 American Ale
Water: Burgdorf Mash: 8.5 L (2.2 gal), sparge: 18 L (4.8 gal) @78°C (172°F)
Rest: Mash in @66°C (151°F), 60 min @66°C (151°F), 15 min @ 78°C (172°F)
Boil: No boil
Fermentation: Primary Close to 1 month @20°C (68°F) in plastic fermenter
Secondary 2 weeks @20°C (68°F) in plastic fermenter
Maturation: Carbonation (CO2 vol) 2 with sugar addition
Maturation time Weeks to months at 15°C (59°F)

06/08/2013: Brew day. Crushed malts, mashed in at 66°C (151°F) and left the mash rest for one hour. Then let the mash cool down to 38°C (100°F) and left it there for 4 days. Then added the Nelson Sauvin hops and heated up to 78°C (172°F), sparged, cooled the wort down to roughly 20°C (68°F) and added an added some WY1056 and left the fermenter untouched for nearly 1 month.

07/07/2013: Racked the beer off the yeast and added the first 75 g of Nelson Sauvin hops.

07/14/2013: Added another 75 g of Nelson Sauvin hops.

07/21/2013: Bottled the beer with a sugar addition to a carbonation level of 2 vol of carbon dioxide and added EBY020 B. jurassienne I or EBY021 B. bruery I to the bottles. I store the bottles at 15°C (59°F) since.

10/27/2013: Beer now 3 months in bottle. Its time for a first official tasting.

NelsonSauvinedBerlinerWeisseVersion with B. bruery I (EBY021, glass on the right):

Aroma: Lots of white grapes and citrus character, some faint funk in the background. Very impressive aroma. Some H2S in the nose (foul eggs) as one swirls the glass.

Appearance: Straw yellow, hazy, nice bubbles rise to the top and form a two finger white head

Flavor: White grapes, citrus character, light Pilsner malt character (something between honey, corn and bread), some barnyard funk and light level of sourness in the finish. Very damn tasty!

Mouthfeel: Light body, average carbonation level (for the style), dry finish, hint of funk and sourness in the aftertaste

Overall Impression: There are a lot of the typical Berliner Weisse aroma and taste characteristics present in this beer with one exception: the sourness. It is far from what I would expect from a Berliner Weisse. I don’t know if the sourness will increase by further maturating the beer. We will see. Anyway, this is a very neat beer: light, fruity with a hint of sourness.

Version with B. jurassienne I (EBY020, glass on the left):

Aroma: Subtle fruit character compared to the EBY021 version. This one is more funky and is driven by leather, horse blanket and a hint of citrus in the back. Some H2S in the nose (foul eggs) and a hint of musty, cellar-funk in there as well. By all means not clean… In one word: funky! Gets more approachable as it warms up.

Appearance: Straw yellow, clear, nice bubbles rise to the top and form a two finger white head

Flavor: White grapes and citrus character. Very dry and not a lot of the backbone shines through. Light level of sourness in the finish however more prominent than in the EBY021 example.

Mouthfeel: Light body, average carbonation level (for the style), dry finish. This example finishes with a funk-fest in the mouth (leather, clove, barnyard and some tartness)

Overall Impression: Completely different from the EBY021 version. A very funky example where the hops kind of play in the background. Gets kind of cleaner as it warms up as all the really annoying flavors (H2S, mustiness) kind of disappear.

I actually prefer the EBY020 version because it is so refreshing, fruity and light. The EBY021 leads to a rather funky beer which makes it a bit less refreshing in my opinion. It seems to me that the EBY020 Brett strain is not as powerful as EBY021. EBY020 is more on the fruit side where EBY021 really hits you in the face with its funk. Well, EBY021 will get into my next Berliner Weisse again. And the next Weisse will be dry hopped as well. The Nelson Sauvin hops match perfectly with the profile of the Weisse. As both EBY020 and EBY021 are tested in the BBA/EBY Brettanomyces experiment, I am really looking forward how these two strains perform. I haven’t actually brewed my share of the experiment yet as I am way behind my brewing schedule already. However, I will brew the batch for the experiment before the end of the year.

#25P Decoction Wheat

Eureka, yet another post about a recipe from the old days. April 2011 in this case. This time about my first decoction batch I conducted. Decoction is basically a technique where one heats up only a small part of the mash in a separate kettle and pours it back to the main mash to raise the temperature. Therefore a different technique to raise the temperature of your mash instead of direct heat. Decoction mashes are very common in wheat breweries and some say that it has a major impact on the flavor of a beer.

I did a decoction mash on a small-scale to test how it works. The recipe is straight forward with some acidified malt to adjust the mash pH at the beginning.

Recipe: Decoction Wheat
Numbers: Volume [L] 5 (1.3 gal)
Original gravity 13.5°P (1.054)
Terminal gravity 5°P (1.020)
Color Around 4 EBC
IBU 13 IBU
ABV 4.7% (v/v)
Grains: Pilsner malt (4 EBC) 0.52 kg
Wheat malt (4 EBC) 0.65 kg
Acidified malt (9 EBC) 0.025 kg
Hops: Hallertauer (8% AA) 3.3 g and boil for 90 min
Yeast: Wyeast’s #3068 Weihenstephan
Water: Burgdorf Mash: 4 L (1.1 gal), sparge: 5 L (1.3 gal) @78°C (172°F)
Rest: Mash in @40°C (104°F),
25 min @50°C (122°F),
20 min @64°C (147°F),
60 min @71°C (160°F),
10 min @ 78°C (172°F)
Boil: Total 90 min
Fermentation: Primary 14 days @18°C (64°F) in plastic fermenter
Secondary N/A
Maturation: Carbonation (CO2 vol) 3.5 with sugar addition
Maturation time > 3 weeks

04/16/2011: Another pilot batch brew day. Crushed all the grains and mashed in at 40°C (104°F) and then let the temperature rise to 50°C (122°F) by directly heating the mash. After the 25 min rest, I removed 50% of the mash and heated this share up to 71°C (160°F), then let this share rest for 15 min and heated up to a boil and boiled for 20 min. Afterwards, the boiled share was poured back to the main mash to increase the mash temperature from 50°C to 64°C (147°F). After a 20 min rest I increased the temperature again by direct heat up to 71°C (160°F), rested for 60 min and then prepared for the mash out at 78°C (172°F). Sparged with 5 L of 78°C (172°F) water and collected the runnings. Then boiled the wort with the small Hallertauer hops addition for 90 min, cooled the wort down to 20°C (68°F) and added freshly propagated #3068 Weihenstephan yeast.

05/01/2011: Bottled the beer after a primary fermentation step of roughly 14 days and added enough sugar to get a carbon dioxide level of 3.5 vol. Then stored the bottles at room temperature for another seven days and then stored the bottles in my refrigerator.

Tasting:

Aroma: Slight banana aroma, grainy and a bit of sulphur detectable.

Appearance: Yellow-gold, white creamy head, nice carbonation level. Poured the yeast sediment into the glass as well.

Flavor: Rather subtle banana character, hint of grains…

Mouthfeel: Light to medium body, lively carbonation level, short light grainy aftertaste. Easy to drink.

Overall Impression: This is a wheat beer but without any special character I expected from the decoction mashing like some caramel or even some burnt character. In my opinion, the decoction mash did not contribute to additional flavors or aroma I could taste. Either the technique was not right or I simply can’t taste the differences.

I haven’t done any decoction mash since simply because I do not brew any wheat beers anymore (brewed enough of it). However, all future batches of Lambics will be brewed using the traditional turbid mash technique which is kind of a decoction mash technique as well. In this case, my Lambics improved a lot since I switched from traditional infusion mashes to the turbid mash. And I can clearly taste the difference there. Cheers!

#31 Dunkelweizen

Eureka, today about a recipe I designed myself and brewed three times already. The recipe below is for a relatively straight forward Dunkelweizen (dark wheat beer, BJCP category 15B). I like dark beers in general and decided to create a darker version of a wheat beer. No further introduction, let’s go through the recipe:

Recipe: Dunkelweizen
Numbers: Volume [L] 20 (5.3 gal)
Original gravity 14°P (1.056)
Terminal gravity 5.4°P (1.021)
Color Around 30 EBC
IBU 12 IBU
ABV 4.7%
Grains: Munich malt (14.5 EBC) 1.0 kg
Wheat malt dark (16 EBC) 2.6 kg
Pilsner malt (4 EBC) 1.0 kg
Cara Wheat (115 EBC) 0.3 kg
Carafa Typ 1 (900 EBC) 0.06 kg
Acidified malt (4 EBC) 0.15 kg
Hops: Hallertauer (8% AA) 12 g and boil for 90 min
Yeast: Wyeast’s #3068 Weihenstephan
Water: Burgdorf Mash: 3.4 L (0.66 gal),
sparge: 20 L (5.3 gal) @78°C (172°F)
Rest: Mash in @47°C (117°F)
20 min @45°C (113°F)
add acidified malt, 15 min @53°C (127°F)
30 min @63°C (145°F)
40 min @72°C (162°F)
10 min @ 78°C (172°F)
Boil: Total 90 min
Fermentation: Primary 7 days @20°C (68°F) in plastic fermenter
Secondary None
Maturation: Carbonation (CO2 vol) 3.5 with fresh wort
Maturation time 3-4 weeks

05/13/11: Brew day number 31. All went according to the protocol above. Crush all the grains as mentioned in the recipe but crush the acidified malt separately. Then mash in at 45°C (113°F) but not the acidified malt. This malt is added after the 20 min rest at 45°C (113°F). The reason for this is to prevent a lower mash pH during the ferulic acid rest at 45°C. For further information have a look at a previous post of mine #48 Dunkler Nachthimmel.

Fig 1: Dunkelweizen mash

Then do the next rests at the mentioned temperatures, then sparge and boil the wort for 90 min with the hop addition. This beer is not about hops and therefore only a small amount of hops is added.

Fig 2: Collecting the Dunkelweizen wort

After the boil fill 10% of the wort’s volume into clean, disinfected glass bottles. In my case 2 L (0.53 gal). This fresh wort is needed at bottling to get the right amount of carbonation. Store the fresh wort in a refrigerator. Cool down the rest of the wort to pitching temperature of about 20°C (68°F) and pitch healthy Wyeast’s #3068 Weihenstephan yeast or any other wheat yeast you want.

I bottled the beer directly after a primary fermentation of seven days. I used the fresh wort to get the right amount of carbonation (3.5 vol of carbon dioxide). And there are enough yeast cells in the fresh beer. So no need to add fresh yeast at bottling. Please check whether your bottles can handle such high carbonation levels! Otherwise, you will have a lot of bottle bombs…

I then leave the bottles at fermentation temperature for another week or two and then store the bottles in a refrigerator. The beer is ready to drink within three weeks after bottling.

Tasting:

Aroma: Lots of banana, some caramel notes and the typical wheat beer character. No sulphur. Very nice aroma. Makes you thirsty!

Appearance: Brown color, the yeast in suspension makes it cloudy. Three finger tan, frothy head with a lot of bubble rising to the top.

Flavor: Pretty much the same notes I could detect in the aroma. Banana in the front, some caramel character, hints of spicy, phenolic notes.

Mouthfeel: Light-medium body, lively carbonation. Finishes with a malty and fruity aftertaste. The light-medium body makes it a bit heavier than a normal, pale wheat beer. However, the higher body does not make it less enjoyable. It is still a very easy to drink beer.

Overall Impression: I really like this beer. It has all the characteristic aroma, flavor profile you would expect from a wheat beer. Plus some additional character from the darker malts such as caramel. I am pretty satisfied with this recipe and would not change anything.

#23P Single Wheat Experimental Batch (SWaSH)

Eureka, today’s post is about another SMaSH (single malt and single hop) experiment. The reason for doing this recipe was to find out how a single wheat malt beer would taste like and to find out whether it is possible to brew a 100% wheat beer in the first place. I therefore call this kind of beer SWaSH for single wheat and single hop. One problem with such a setup is the fact that wheat malt does not have husks as most of the barley malts. These husks are necessary for lautering with a perforated bottom to get a kind of filter bed. Without such husks one could imagine that the wheat malt plugs the perforated bottom and makes a lautering relatively hard or even impossible. However, I have no experience with a 100% wheat malt based beer and a perforated bottom. I chose to do a brew in a bag instead to circumvent the lautering with my perforated bottom. That’s basically the most exciting part abput this recipe:

Recipe: SWaSH
Numbers: Volume [L] 5 (1.32 gal)
Original gravity 12°P
Terminal gravity 4.8°P
Color Around 4 EBC
IBU 10 IBU
ABV 4%
Grains: Wheat malt (4 EBC) 1 kg
Hops: Tettnanger (4.2% AA) 3 g and boil for 60 min
Tettnanger (4.2% AA) 2.5 g and boil for 30 min
Yeast: Wyeast’s #3068 Weihenstephan
Water: Burgdorf Mash: 2.5 L (0.66 gal), sparge: 4 L (1.1 gal) @78°C (172°F)
Rest: Mash in @47°C (117°F), 45 min @45°C (113°F), 15 min @53°C (127°F), 30 min @63°C (145°F), 40 min @72°C (162°F), 10 min @ 78°C (172°F)
Boil: Total 60 min
Fermentation: Primary 5 days @20°C (68°F) in plastic fermenter
Secondary N/A
Maturation: Carbonation (CO2 vol) 4 with sugar addition (40 g sugar to 4.5 L beer)
Maturation time 14 days

02/26/2011: Brew day. I chose to do a small SWaSH batch with 1 kg of wheat malt and some Tettnanger hops. I then preheated the mash water up to 47°C and inserted the malt bag into the kettle and added the crushed wheat malt. I then did the rests as mentioned in the recipe and pulled the bag out after resting at 78°C for 10 min and washed the grains with the sparing water. By the way, the iodine test was negative. Boiled the wort for 60 min with the small hop additions and cooled the wort down to 20°C (68°F) and added 25 billion (2.5E10) yeast cells for 5 L of wort.

03/05/2011: Its bottling time. Five days after brew day I bottled the beer with some sugar to get a carbonation level of approximately 4.0 vol of carbon dioxide. I then left the bottles carbonate and mature for nearly 14 days at room temperature and then put the bottles in a refrigerator.

05/07/2011: The beer is now nearly two months in the bottles and its time for a tasting. I tasted the beer before but never did any tasting notes. I kind of forget to do tasting notes and when I do them most of the beers are already past their best-to-drink date…

Aroma: Lots of banana, no hop character and no malt character detectable. Smells like a traditional South German wheat beer.

Appearance: Pale yellow color, lots of carbon dioxide bubbles rise to the top and form a very creamy, white head. Very good head resistance. I added some of the yeast sediment to get the real wheat character.

Flavor: Not a lot is going on here. Banana again and some of the lightly sour, bread, grainy character of the wheat malt is detectable. And the yeast gives the beer the typical yeasty, doughy character.

Mouthfeel: Light body, lively carbonation. Rather short and sweet, malty aftertaste. Very refreshing.

Overall Impression: The beer is still fresh and very refreshing after some time in the bottle. Lots of the characteristic wheat beer character such as banana and the character you get from the wheat malt are present as well. Sure a well made beer. However, it is a bit boring…

It seems that a 100% wheat beer is possible to make and enough enzymes are present in the wheat malt for a complete mash conversion. What about the wheat malt? First of all, the beer tasted like expected. Rather one-dimensional and lots of the wheat malt comes through. Hops are in the background and some of the wheat yeast character comes through as well. That’s what I was going for in the first place with this experiment. At least I now know what the wheat malt can contribute to such a beer.

Comparing the flavor profile of this beer with other homemade wheat beers from the past and some commercial examples, going the extra mile with a 100% wheat malt beer does not seem to have a big impact on the beer. I therefore can’t see any advantages brewing a 100% wheat malt based beer compared to a wheat beer made with 50% wheat malt and 50% barley malt. Thanks for reading and commenting if you like and stay tuned!

#7 Zelebrator Weizenbock

Eureka, its time for another recipe from the past. Today’s recipe is a recipe for a wheat bock (Weizenbock in German). A wheat bock is basically a Dunkelweizen brewed to bock strength. For further information about the style please have a look at the BJCP style 15C Weizenbock. The following recipe is not a recipe for a traditional Weizenbock since bocks are traditionally made with a decoction mash. I went with an infusion mash instead.

Recipe: Zelebrator Weizenbock
Numbers: Volume [L] 15 (4.0 gal)
Original gravity 18.5°P
Terminal gravity 6.4°P
Color Around 23 EBC
IBU 5 IBU
ABV 7 %
Grains: Pilsner malt (4 EBC) 1kg
Wheat malt (4 EBC) 2 kg
Munich malt 1 (14.5 EBC) 1 kg
Carafa Typ 1 (900 EBC) 0.02 kg
Hops: Hersbrucker (3.6% AA) 14.2 g and boil for 70 min
Hersbrucker (3.6% AA) 14.2 g and boil for 1 min
Yeast: Saflager S04
Water: Burgdorf Mash: 12 L (3.2 gal), sparge: 9 L (2.4 gal) @78°C (172°F)
Rest: Mash in @45°C (113°F), 20 min @45°C (109°F), 30 min @61°C (142°F), 30 min @72°C (162°F), 10 min @ 78°C (172°F)
Boil: Total 70 min
Fermentation: Primary 4 days @ 20°C (68°F) in plastic fermenter
Secondary None
Maturation: Carbonation (CO2 vol) 2
Maturation time 3 weeks

01/20/07: Brewday number seven. All went according to plan. I had two kettles back then, one for mash (on the right side) and one for the hot water (left).

I even had a old-school stirrer made out of a windshield wiper motor. Unfortunately, the motor got hot very fast and stopped… Not a good qualification for a mash stirrer… Nevertheless, the mash went great and the iodine test was negative at the end. Then boiled the wort for 70 min with the addition of the hops and added the yeast after it reached the right pitching temperature.

01/24/07: Bottled the beer after four days already. The gravity was around 7°P and the forced fermentation test ended at 6.4°P. The remaining 0.6°P should be enough to carbonate the beer. I then left the bottles carbonate and mature for three weeks at cellar temperatures and stored them in my cellar until further use.

Unfortunately, I do not have any pictures of the finished beer and somehow lost my tasting notes. This is the last batch where I do not have any tasting notes. Although further batches will not have pictures of the beers… Sorry for that. I wasn’t planning on writing about the beers back then. Stay tuned for further recipes!