This was my first attempt at making encapsulated yeast and fermenting wort with them.
Objective:
To make encapsulated yeast and ferment two 3L batches of a beer. One is fermented with a traditional yeast slurry (the "control"), the other is fermented with the yeast beads. Do sensory analysis to see how much different each batch tastes.
Prediction:
Encapsulating yeast in alginate beads will ferment out a wort solution faster than a yeast slurry, and will allow for easy separation of the yeast beads from the finished fermented wort. No prediction on how they will taste (in terms of sensory terms), other than different.
Materials needed:
Tap Water
Distilled Water
DME
hops
sodium alginate
yeast (Safale-US05)
yeast nutrient
calcium chloride
Process:
Yeast starter
I use a 100g DME/1000ml tap water ratio. I created a 2L starter (200g DME/2L tap water) with a pinch of yeast nutrient. I pitched the dry Safale-US05 in the starter on the stir plate to get it going. I know you aren't supposed to do yeast starters with dry yeast, but I do anyways because it at least gets the yeast really primed and ready to ferment with a slower lag phase. I have no evidence yet if what I am doing actually helps. I guess I just want a larger yeast count? Anyways, this is what I did.
Wort creation
To make 6L (or about 1.5 gallons of beer) to be split into two 3L batches, I used 1.5 lbs of DME, and 1.5 gallons of water....in a 2 gallon pot. I had to split the wort up and put 2L into a smaller pot to prevent a boil over. I need to get a larger pot...
Once the larger pot was boiling, I added 6g of old Nugget whole leaf hops to give some bitterness. With one minute remaining in the boil, I added 6g of old Saaz whole leaf hops for some aroma.
I cooled the wort as rapidly as possible in an ice water bath in the kitchen sink.
Beads creation
(Backing up to the previous Thursday before explaining this experiment's bead creation...)
The previous Thursday I made up a 4% Sodium Alginate Solution (4g alginate/100ml distilled water). The solution was so incredibly thick I could hardly stir it into a consistent solution nor could my immersion blender even sink its teeth into mixing it evenly. So I added 100% more water to make a 2% solution. I was worried this was too thin. Before adding any yeast, I tested out the creation of beads in the 3% calcium chloride solution. The 2% alginate created REALLY tough beads. My gauge of "toughness" was how much effort it took to crush a bead between my fingers. I figured the tougher the bead, the thicker the membrane and the slower the diffusion of the beads. So I made 1% and 0.5% solutions and tested each. 0.5% was too thin and would crush too easily, while the 1% felt like it had a sweet spot. It would still crush, but didn't feel fragile. My 2% "stock" solution had lots of bubbles in it at this point, so I let it sit because I was leaving for the weekend and had no time to conduct this experiment.
(And now for this experiment's bead creation...)
By now the 2% "stock" sodium alginate solution had no more bubbles in it. I had cleaned the yeast from my starter had about 200ml of pure yeast to use for this experiment. Because each batch was 3L of volume, I had no idea how much volume of beads to create. Because I needed some of the yeast to pitch as a direct slurry and the rest to make beads, I figured a 10% volume of beads would be a great starting point. This would be 300ml of beads. This would mean to create a 1% alginate bead, I would need to cut the 2% stock in half with yeast. So that means take 150ml of the yeast slurry and mix with 150ml of the 2% alginate to make 300ml of beads. The remaining 50ml of yeast would act as the slurry in the "control" batch.
With 300 ml of alginate/yeast mixture, it was time to make the beads. I used a brine injector without its needle to make the alginate/yeast droplets to drop into the calcium chloride solution. Because this was a 1% SODIUM alginate/yeast mixture, and because the reaction to create the beads is a replacement reaction where the sodium ions of the sodium alginate swap with the chloride ions of the calcium chloride solution, the sodium ion is going to be the limiting reactant, so as long as the calcium chloride solution is greater in volume and greater in chloride % than the alginate/yeast mixture, then the calcium chloride bath won't "run out" of chloride ions.
So now the process of creating the beads was mechanical at this point. Use the brine injector to suck up around 30+ml of alginate/yeast mixture, then slowly drop droplets into the calcium chloride bath. This took awhile to create 300+ml of beads. I also noticed that the closer to the calcium chloride bath the beads were dropped, the more tear dropped they were shaped. Whereas the higher they were dropped, the more spherical they were shaped. Spherical is better = more surface area.
I actually wound up with a little more than 300 ml, but it was ok. I figure the more the better.
Fermenting:
After filling each 1 gallon jug with the split wort, and after pitching the control with 50ml of yeast slurry and the other jug with the beads, I placed them on a plant heating mat with a temperature controller set to 72*F. A placed boxes from 3 gallon carboys over each jug to keep the wort from sunlight and to create even heating and preserve heating.
Data:
I collected data every 12 or so hours. I used a brix refractomer and relied on a correction calculator to correct fermented brix values as well as convert to gravity. The data is below.
| Brix | Adjusted Gravity | |||||
| Date | Slurry | Beads | Beads Comments | Date | Slurry | Beads |
| 10/31/2016 17:00:00 | 10 | 10 | 10/31/2016 17:00:00 | 1.04 | 1.04 | |
| 11/1/2016 7:00:00 | 8.5 | 8 | Maybe? | 11/1/2016 7:00:00 | 1.029 | 1.026 |
| 11/1/2016 17:00:00 | 6 | 9.25 | huh? | 11/1/2016 17:00:00 | 1.014 | 1.034 |
| 11/2/16 7:00 AM | 4.75 | 9.5 | nothing is happening | 11/2/16 7:00 AM | 1.006 | 1.035 |
| 11/2/16 7:00 PM | 4.75 | 8.5 | something is happening, its making lots of micro bubbling noises | 11/2/16 7:00 PM | 1.006 | 1.029 |
| 11/3/2016 7:00:00 | 4.75 | 9 | Lots of little bubbles and more popping bubble sounds. Not as clear | 11/3/2016 7:00:00 | 1.006 | 1.032 |
| 11/3/16 5:30 PM | 4.75 | 8 | Slightly cloudy, very active | 11/3/16 5:30 PM | 1.006 | 1.026 |
| 11/4/16 9:00 AM | 4.75 | 6 | kinda of clearer? Lots of little bubbles. Humming away | 11/4/16 9:00 AM | 1.006 | 1.014 |
| 11/4/16 10:00 PM | 4.75 | 5.1 | Still lots of bubbling noises | 11/4/16 10:00 PM | 1.006 | 1.008 |
| 11/5/16 9:00 AM | 4.75 | 4.95 | Still lots of bubbling noises | 11/5/16 9:00 AM | 1.006 | 1.007 |
| 11/6/16 8:00 AM | 4.75 | 4.5 | A lot quiter. Very Clear. Done? | 11/6/16 8:00 AM | 1.006 | 1.004 |
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| This was taken about 12 -24 hours in. |
Data comments:
Both batches' airlocks were bubbling within 5 hours. My first reading 12 hours in had me really excited as the beads had dropped further than the yeast slurry. However I think that was a false reading. The following 4-5 readings really gave no direction as to what the beads were doing. It wasn't until the evening of 11/3/16 that it was clear the beads were actually doing something.
Results:
The yeast beads worked. They didn't work as fast as the yeast slurry, but they worked. Despite working slower, they did attenuate further than the yeast slurry and kept a very clean ferment, as in no haziness in the ferment. The "control" batch had a classic heavy swirling cloudiness during ferment and is slowly clearing as the yeast flocculates. There was only a day or two of cloudiness in the beads batch, and this paled in comparison to the yeast slurry batch.
 |
| Finished Ferment. The clarity is amazing in the beads |
Analysis:
I think I way over pitched the yeast slurry. Never seen a batch ferment out in 1.5 days. There was quite a lag with the beads, but once they got going, it actually fermented out the batch almost as quickly compared to the slurry, though not quite as fast. But what is the equal amount of yeast to be used in a comparison ferment like this? 50ml of 3000ml is 1.67% of volume whereas I used 5% of volume with the initial 150ml of yeast slurry for the beads. I am going to leave this as a question to be answered later.
It is kind of hard to tell, but I am not sure if 100% of the beads were fully submerged into the wort. This might mean that only the beads on the bottom (weighted down by beads above) were doing all of the work? What would happen if 100% of the beads were submerged in the wort?
It is kind of hard to tell, but I am not sure if 100% of the beads were fully submerged into the wort. This might mean that only the beads on the bottom (weighted down by beads above) were doing all of the work? What would happen if 100% of the beads were submerged in the wort?
Sensory Analysis:
| Sensory Analysis | Slurry | Beads |
| Appearance | Super Hazy, almost like a Wit | Crystal Clear, Like a lager |
| Aroma | Very Floral, Almost Saison Like | A layer of floral has been stripped off. Almost chemical |
| Flavor | Ok | Not great |
| Bitterness is softened | bitterness is HARSH | |
| Some breadiness from the yeast | Chemical smell comes through as chemical flavor | |
| Mouthfeel | Soft, chewy | Still soft, slightly thinner, but not much |
| Overall | Terrible recipe to begin with, but better than the beads | Terrible recipe to begin with, and a terrible beer. NOT good at all! |
Yes, the recipe I used for this beer was terrible. I guess I added hops to make sure other things didn't start growing in there? I guess (and this was a happy accident) I never thought much about how the bitterness and aroma characters would carry through. When you only ferment with a yeast slurry, that is all you know in terms of how a beer will ferment. It is not until you have a side by side like this when you realize just HOW bitterness and aroma can be affected simply by the ferment.
I also took for granted just how much flavor yeast will add to your beer. The yeast beads simply had ZERO yeast character (which was kind of the point...) but in comparison it gives you an awesome perspective on HOW yeast adds flavor to a beer.
I also took for granted just how much flavor yeast will add to your beer. The yeast beads simply had ZERO yeast character (which was kind of the point...) but in comparison it gives you an awesome perspective on HOW yeast adds flavor to a beer.
Final thoughts:
Going forward I should have harvested the beads as soon as fermentation was done and immediately added them to the next new batch to see if they are "primed" and ready to immediately start fermenting. I should do this side by side with some brand new beads. And I should do two versions of the beads (so 3 one gallon batches side by side), one with the same % of alginate, and one with 1/2 the % of alginate to see if a thinner membrane of the beads will allow quick diffusion of sugar to alcohol.
As for actually using this method for making a good beer? The sensory analysis shows A) don't make a shitty beer to begin with. B) Don't even think about making a beer where you want the yeast to add any character to the flavor: Hefeweizen, Saison, pretty much anything Belgian, the list goes on.... C) I guess the only thing "good" about the beads beer was that the aroma came through and was terrible, but not as terrible as the flavor? I am stretching here. Maybe a NE IPA could be a candidate? I am cringing...
As for actually using this method for making a good beer? The sensory analysis shows A) don't make a shitty beer to begin with. B) Don't even think about making a beer where you want the yeast to add any character to the flavor: Hefeweizen, Saison, pretty much anything Belgian, the list goes on.... C) I guess the only thing "good" about the beads beer was that the aroma came through and was terrible, but not as terrible as the flavor? I am stretching here. Maybe a NE IPA could be a candidate? I am cringing...
