Cider Blend 2020: How does it compare?

As a student from the University of Guelph, I was hired on by Escarpment Labs for a Co-op placement back in the summer of 2020. Due to COVID restrictions, I found myself working from home a couple days a week for the first month of my work term. During the days at home, I was given a project in which I performed a fermentation of my choice in hopes of becoming better versed in fermentation processes and simultaneously creating something delicious. After some thought I had settled on creating some cider and wrote this post to provide some in-cider information on the process.

 With a plethora of characteristics and flavour profiles, I feel that it is safe to say that there is definitely a cider out there for everyone. However, with that being said, there hasn’t been a yeast that has been created specifically for cider fermentation. The most popular yeasts used by cider industries consist mostly of sparkling wine, white wine or ale yeasts. There is also a strong history of cideries using wild yeast as well, as wild yeast can often be found in orchards. Since such a wide range of yeasts can be used in cider making, I decided to conduct some trial cider fermentations using a sourdough starter and Escarpment Labs Cider Blend 2020 (for those who missed out, also try JÖTUNN for your ciders). 

 I chose to give sourdough starter a try as I felt that it was a more common and easily accessible yeast that people are more likely to have in their homes. If the sourdough yeast was able to produce a pleasant flavour, it would open up opportunities for people to try their own cider fermentations. In addition, I fermented a cider using Lalvin D47 White Wine Yeast to use as a control. This would allow me to compare the flavours of my two trial yeasts with the flavours of a yeast used in the current cider industries.

For this project, I used an apple juice blend that contained sweet Norfolk County apples and some tart Gala apples. The original gravity (OG) was measured with a portable density meter (DMA 35) from Anton Paar to be 1.047. Both the sourdough starter and Cider 2020 Yeast Blend were obtained from Escarpment Labs whereas the D47 yeast was obtained from KJ Urban Winery, a local homebrew shop in Guelph. The Cider 2020 Yeast Blend contains our Saison Nouveau and KRISPY strains that are combined in a 1:1 ratio of total cells.

A standard pitching rate of 0.75 Million cells/mL/°Plato was chosen, and a calculated amount of each yeast slurry was added to jugs, each containing 2L of the apple juice blend. 3-piece airlocks were used during the fermentation process which was allowed to proceed for 25 days. Specific gravity readings were taken for each of the three ciders every other day and is displayed in Figure 1.

The ciders were cold crashed by storing the ferments in Escarpment Lab’s cold room storage, allowing the suspended yeast to settle to the bottom of the jugs and effectively stopped fermentation. Calculated amounts of Potassium Sorbate and a 10% sulfite solution, a mixture of Potassium Metabisulfite and water, were added to the ciders to stabilize them. The sulfites reduce O₂ from the cider producing a non-ideal environment for microbes, whereas the sorbic acid impairs the reproductive ability of yeast and mold cells (Winemakers Academy 2020).

After allowing the ciders to stabilize for a few days, they were then decanted into new 2L jugs and placed back into the cold room to let any leftover yeast settle. The samples were then force carbonated. A sensory test was then conducted with my fellow Escarpment Labs employees and feedback was collected and arranged in Table 1. The observations made were all very similar with opinions on a favourite seeming to alternate between D47 and the Cider 2020 Blend.

Lalvin D47 White Wine yeast can enhance mouthfeel due to its ability to produce polysaccharides during fermentation (Lallemand Brewing 2020). It releases high amounts of polysaccharides into the must providing a round soft palate with good weight (Lallemand Brewing 2020). It is for this reason that the flavour profile of the cider fermented with D47 yeast was described to be lighter and more balanced with a good body. This yeast also possesses ß-glucosidase activity which facilitates the expression of the terpenes citronellol, nerol and geraniol (Lallemand Brewing 2020), all of which are aromatic and flavour compounds that are found in plants (e.g. hops) (Beer and Brewing 2020). 

            Both the Saison Nouveau and KRISPY yeast strains in the Cider 2020 Blend produce clean and lightly fruity flavours, contributing to the aromatic apple-y flavours that were detected. Saison Nouveau is POF+, meaning the ferulic acid decarboxlyase gene is functional, allowing the yeast cell to produce phenols. Phenols can contribute a wide range of unique flavours to a beer and may explain the spice that was detected during the sensory analysis. Both strains also possess high fermentation rates which is reflected in the steep slope, and therefore faster fermentation, in the initial days of this project (Figure 1).

            Sourdough starters contain a plethora of different yeast strains as well as naturally occurring lactic acid bacteria. Lactobacillus, more commonly known as “Lacto” in the beer industry, is a Gram-positive lactic acid bacterium (BYO 2020). It is a facultative anaerobe meaning that, although it doesn’t require O₂ to grow, it doesn’t experience any adverse effects in the presence of O₂ either and is still able to multiply. This bacterium is able to metabolize hexoses and pentoses, which can be found in the must, and produce lactic acid, acetic acid and CO₂. The lactic acid is the main contributor to a sour taste and, along with the acetic acid, can explain the acidic and slightly vinegar-y taste that was detected.

            Looking at the collected feedback, the sourdough starter, although very similar in attenuation and fermentation rate to the other starters, wasn’t that well liked. The acidic and vinegary flavours weren’t well suited for a cider and was described as: “tastes more like apple cider vinegar”. The Cider 2020 Blend on the other hand, compared well against the D47 Wine yeast and was preferred by many. Escarpment Labs have successfully created a yeast blend specific to ciders which produces flavours that complement the apple-y aroma of the drink. I feel that the Cider 2020 Yeast Blend is a must try for anyone looking to create and enjoy a delicious cider.

Rona Zhou is a University of Guelph co op student who joined our team in 2020. Are you a student who is interested in an internship?  Check out the co op experience at Escarpment!

References

Beer and Brewing. [25 November 2020]. Available from: https://beerandbrewing.com/dictionary/kzazjsY3RA/

Brew Your Own. [25 November 2020]. Available from: https://byo.com/article/brewing-with-lactobacillus/

Lallemand Brewing. [25 November 2020]. Available from: https://www.lallemandbrewing.com/en/united-states/product-details/lalvin-icv-d47/

Winemakers Academy. [24 November 2020]. Available from: http://winemakersacademy.com/potassium-sorbate-wine-making/#:~:text=The%20sulfites%20from%20potassium%20metabisulfite,and%20molds%20unable%20to%20reproduce.