Homebrew Experiment: Does Yeast Nutrient Matter?
Ride the Lightning: Yeast Lightning Split Batch
I’m a homebrewer. Like most homebrewers, I have no formal education in brewing. I’ve learned my craft through countless hours of reading, sharing conversations with members of the homebrew community, and lots, and lots, of trial and error. It is a labour of love. Along my homebrewing journey, I have picked up habits and practices that I assume to be true; I don’t know them to be true. I aim to learn if all those ‘little things’ we do on the homebrew scale really have an effect on our final product. This blog series is going to put some of these habits and practices to the test.
The addition of yeast nutrient to my wort is definitely one of those little habits in homebrewing that I have picked up over the years. For as long as I can remember, I would add a teaspoon of powdered yeast nutrient into my beer. Since my batches mostly turned out drinkable, I figured that it must be beneficial.
Fermentation, after all, is the magic that turns sugary wort into the delicious finished product that we know and love. If the yeast is happy, the beer will be good. I never paid much attention to the type of yeast nutrient I was using, I simply grabbed whatever was on the shelves at the local homebrew shop. I started to really question things a little more after reading a blog post from Richard Preiss on the Escarpment Labs blog. According to Preiss, not all yeast nutrients are created equal. Why was I carefully selecting all my other ingredients and tuning the water profile so carefully while at the same time just adding a teaspoon of mystery nutrient? Escarpment Labs had the solution: Yeast Lightning. I was excited to put their claims to the test.
To evaluate the differences in a batch of beer fermented with Yeast Lightning nutrient and one with no added nutrients.
To test the prowess of the Yeast Lightning, I brewed a single 6 gallon batch and split it between two fermentors, one with the yeast nutrient and one without. Both batches would use the same type of yeast, Escarpment Labs Irish Ale. The pouches selected were 3 months old at the time of use, which would really put both the yeast and the Yeast Lightning to the test. I wanted to brew something simple and really test the yeast so I decided to go with a low-ABV dry Irish stout. This would give me a dark, roasty, bitter and creamy ale which was low in alcohol. Coming in at only 4%, there aren’t too many non-fermentable sugars in this beer style so a complete fermentation is extra important.
Recipe: Dry Irish Stout
Batch Size - 23L
Original Gravity: 1.043
Final Gravity: 1.011
Colour: 34 SRM
- 70% Maris Otter
- 20% Flaked Barley
- 10% Roasted Barley
- 49°C for 15 minutes
- 64°C for 60 minutes
- 74°C for 15 minutes
- 1.5 oz. of Willamette (6.8% AA) @ 60 minutes
- Escarpment Labs Irish Ale
- 18°C for 7 days
- 21°C for 3 days
Brewfather link to the full recipe including water profile: https://share.brewfather.app/kbYhJAmvRsxTxT
For Yeast Lightning, Escarpment Labs recommends adding it to the boil right before cooling. Since I was splitting the batch after cooling, I pulled off a couple of litres of boiling wort and added 1g of Yeast Lightning. After I cooled the wort and split the batch into separate fermentors, I added the Yeast Lightning wort back into the correct fermentor.
Both batches were placed into separate fermentation chambers and left to ferment at 18°C. Here’s where the fun part comes in. In order to track the fermentation process, I used a pair of iSpindels. These little gizmos are wireless, digital hydrometers and temperature sensors that will float in the wort as it turns into beer. As the wort ferments, the angle of the iSpindel floating in the wort will change. Through the magic of science and the wonders of the cloud, we can see where the fermentation is at any point in time. Over the next seven days, I kept a close eye on my fermentation and was shocked with what I saw (pun intended).
The batch with the added Yeast Lightning took off. The lag-time was three hours less than the non-nutrient batch and it ended up fermenting to about 85% completion in three days less than the batch with no nutrient. After seven days, I raised the fermentation temperature to 21°C and let both batches complete their fermentation. After the 10th day, both beers were sitting nicely at their intended final gravity of 1.011. All that was left to do was to cold crash and package the beer.
Cold crashing your beer at the end of fermentation is one of the best ways that homebrewers can get crystal clear brews. This process is performed when the beer is fully fermented and ready to be packaged. It involves lowering the temperature of the beer to near-freezing and holding it there for about 24 hours. The goal of cold crashing is to force any remaining yeast still floating around in your beer to drop to the bottom of the fermentor.
The problem with reducing the temperature quickly is that it creates negative pressure within your fermentor. That negative pressure can cause water from your blow off tube or bubbler to get sucked into your beer. After the water is sucked in, there is nothing to protect your beer from the dreaded effects of oxygen, which can introduce a wide variety of off-flavours. To combat this, I replace my blow off tube with an empty pop bottle filled with 3-4 psi of CO2. This little bit of pressure in the pop bottle counteracts negative pressure caused by cold crashing and keeps your beer happy, safe, and away from the negative effects of oxygen.
The results from fermentation showed that the addition of Yeast Lightning led to a faster fermentation. The final test would be to see if it made a difference in the taste of finished product. I conducted a variety of blind taste tests to anyone who would sample my latest beer. Their palates ranged from casual beer drinkers to BJCP certified judges. Each person was given three samples of beer; two from one batch and one from the other. The test would be to see if they could differentiate the unique brew. Afterwards, they were asked which brew they preferred.
Out of a total of 22 participants, only ten were able to correctly identify the unique brew. The individuals who easily identified the unique sample all had sensory training. The casual beer drinkers who sampled the beer were unable to differentiate the unique brew.
When it came to asking the participants which brew they preferred, however, 18 of 22 participants chose the batch that had been fermented with Yeast Lightning. Participants noted its clean taste and drinkability as the reason for their choice.
From my own taste testing, I found that the two beers were noticeably different. The Yeast Lightning beer was cleaner tasting and very easy drinking, whereas the beer without the nutrient had increased yeast derived flavours to it. Both beers were quite good and would both be great Irish stouts in their own right, but the cleanness of the Yeast Lightning batch was apparent when tasted side-by-side.
The fermentation data collected by the iSpindels speak for themselves. The Yeast Lightning definitely made a difference in fermentation rate. The little yeasts were healthy and active right away and throughout the active fermentation.
Data from beer sampling was less conclusive. Although the majority participants preferred the beer with the added Yeast Lightning, less than half of them were actually able to differentiate the beer in a blind triangle test.
Overall, the fermentation data does speak for itself. I trust the data far more than the subjective nature of the human beer samplers. The results showed that by adding Yeast Lightning nutrients to the beer, the fermentation was quicker, healthier, and had a reduced lag time. Now that I know that yeast nutrient is having a tangible and positive effect on my brews, I’m definitely going to keep a pouch of Yeast Lightning in my homebrew kit.
Author: Tyler Ustrzycki, a husband, father, homebrewer and engineer from Waterdown, Ontario. Follow Tyler on Instagram: @grindstonebrew