Author: Jordan Folks
The main source of fermentable sugar in beer is barley malt, and the amount a brewer uses not only determines the ultimate strength of the finished beer, but the overall malt character. For styles that pair strength with dryness, brewers can employ a handful of methods to encourage attenuation, such as mashing cool and using a charge of simple sugar, but this often isn’t enough to accomplish the intended goal. Another option involves introducing exogenous enzymes such as fungal alpha amylase.
Unlike other enzymes that produce glucose, fungal alpha amylase breaks down complex dextrins into maltose, resulting in higher attenuation and thus dryness. It also starts to become inactive at lower temperatures, hence many opt to use it post-boil, typically adding a dose at yeast pitch. In addition to driving attenuation, fungal alpha amylase also serves to break down the starches that lead to haze, meaning it can assist in beer clarity.
I am a big fan of dry beer and rely on a handful of techniques to ensure what I brew is well-attenuated. While mechanical methods have worked quite well for me, I’m intrigued by the use of exogenous enzymes and happened to have some fungal alpha amylase that I picked up in a homebrew club group buy a few years ago. Curious to see how it impacts a German Pils, I designed an xBmt to test it out.
| PURPOSE |
To evaluate the differences between a German Pils that received a dose of fungal alpha amylase at yeast pitch and one that received no fungal alpha amylase.
| METHODS |
For this xBmt, I went with a simple German Pils recipe I felt would allow any impact of the variable to show through. Big thanks to F.H. Steinbart for hooking me up with the malt for this batch!
Cathedral View
Recipe Details
| Batch Size | Boil Time | IBU | SRM | Est. OG | Est. FG | ABV |
|---|---|---|---|---|---|---|
| 5.8 gal | 60 min | 42.2 | 3.3 SRM | 1.045 | 1.005 | 5.25 % |
| Actuals | 1.045 | 1.005 | 5.25 % | |||
Fermentables
| Name | Amount | % |
|---|---|---|
| Pilsner | 11 lbs | 100 |
Hops
| Name | Amount | Time | Use | Form | Alpha % |
|---|---|---|---|---|---|
| Hallertauer Mittelfrueh | 43 g | 60 min | First Wort | Pellet | 2.3 |
| Saphir | 43 g | 60 min | First Wort | Pellet | 2.3 |
| Hallertauer Mittelfrueh | 85 g | 60 min | Boil | Pellet | 2.3 |
| Hallertauer Mittelfrueh | 28 g | 15 min | Boil | Pellet | 2.3 |
| Saphir | 28 g | 15 min | Boil | Pellet | 2.3 |
| Hallertauer Mittelfrueh | 28 g | 10 min | Aroma | Pellet | 2 |
| Saphir | 28 g | 10 min | Aroma | Pellet | 3.5 |
Miscs
| Name | Amount | Time | Use | Type |
|---|---|---|---|---|
| Fungal Alpha Amylase Enzyme | 1 ml | 0 min | Primary | Other |
Yeast
| Name | Lab | Attenuation | Temperature |
|---|---|---|---|
| Global (L13) | Imperial Yeast | 77% | 46°F - 55.9°F |
Notes
| Water Profile: Ca 79 | Mg 4 | Na 10 | SO4 131 | Cl 40 |
Download
| Download this recipe's BeerXML file |
A day before brewing, I prepared a single large yeast starter of Imperial Yeast L13 Global to split between two batches.
The following day, after collecting the full volume of water for two 5 gallon/19 liter batches, adjusting each to the same mineral profile, and getting them heating up, I milled the grain.
With each batch of water properly heated, I incorporated the grains and set the controllers to maintain an initial 60 minute rest at 146°F/63°C followed by a 15 minute rest at 156°F/69°C.
During the mash rests, I weighed out the kettle hop additions.
The worts were boiled for 60 minutes with hops added at the times listed in the recipe. Once complete, I quickly chilled the worts before taking refractometer readings showing they were at the same target OG.
After transferring identical volumes of wort from either batch to sanitized fermentation kegs and letting them chill to my desired fermentation temperature of 48°F/9°C, I evenly split the yeast starter between them.
Next, I added 1 mL of fungal alpha amylase to one batch while leaving the other alone, the amount of which is recommended for improved attenuation.
Following two weeks of fermentation, I gradually raised the temperature to 62°F/17°C for a two-day diacetyl rest, after which I reduced the temperature to 31°F/0.5°C over a few days. Hydrometer measurements taken at this point revealed a difference in FG that aligned with expectations.
After a few more days of cold conditioning, I pressure transferred the beers to CO2 purged serving kegs that were placed on gas in my keezer where they were left for 4 weeks before they were ready for evaluation.
| RESULTS |
A total of 31 people of varying levels of experience participated in this xBmt. Each participant was served 2 samples of beer where no fungal alpha amylase enzyme was added at yeast pitch and 1 sample of the beer dosed with fungal alpha amylase enzyme at yeast pitch in different colored opaque cups then asked to identify the unique sample. In order to reach statistical significance, 16 tasters (p<0.05) would have had to accurately identify the unique sample, though only 11 did (p=0.47), indicating participants in this xBmt were unable to reliably distinguish a German Pilsner that was dosed with fungal alpha amylase enzyme at the point of yeast pitch from one that was not treated with fungal alpha amylase enzyme.
My Impressions: Out of the 5 semi-blind triangle tests I attempted, I correctly identified the odd-beer-out just once. I admittedly perceived these beers as being identical in every way, and they were excellent examples of German Pils – refreshingly crisp, clean, and appropriately bitter with a lovely bouquet of noble hop aroma.
| DISCUSSION |
There are several factors that go into a pint of beer, many of which are determined by the style being brewed, which is certainly the case for dryness. As a function of attenuation, or the amount of sugars in wort that are converted to alcohol and CO2 during fermentation, brewers rely on several techniques to modulate dryness, one being the use of enzymes like fungal alpha amylase. Interestingly, tasters in this xBmt were unable to reliably distinguish a German Pilsner that was dosed with fungal alpha amylase enzyme at the point of yeast pitch from one that was not treated with fungal alpha amylase enzyme.
What makes this result so curious is the fact the addition of fungal alpha amylase did seem to have the intended effect, as the beer dosed with the enzyme finished 0.004 SG lower than the non-dosed batch. However, this didn’t seem to have much, if any, impact on the perceptible qualities of the beer including mouthfeel, which many believe becomes is correlated with attenuation. It’s possible the use of fungal alpha amylase in a higher OG beer, or even a beer that was mashed warmer, might produce a noticeable effect.
I wasn’t really sure what to expect when I was designing this xBmt, and I was pleased to see the batch dosed with fungal alpha amylase had a lower FG than the non-dosed batch, as that’s what it’s supposed to do. But I wouldn’t say I’m surprised neither tasters nor I could tell a difference between these beer, and while I look forward to playing around with enzymes in the future, I’m unlikely to purchase more fungal alpha amylase once this bottle runs out.
If you have any thoughts about this xBmt, please do not hesitate to share in the comments section below!
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5 thoughts on “exBEERiment | Impact Fungal Alpha Amylase At Yeast Pitch Has On A German Pils”
Man, I’d be curious to know whether pitching four pouches of Imperial into a starter does anything other than ensure that each batch got some from each pack.
Interesting experiment and results. I, too, like a dry beer. I like my Kveik yeasts because they seem to finish a bit dry. I wonder how this would have turned out with a yeast that does not attenuate quite as well as L13.
That FAA is over 6 years old and 3x past its expiration date. You might want to at least know the condition of your materials before doing science you publish.
And yet it still works!
It’s brown now but when it’s new it’s light green. It might work a little bit but no where near what it’s supposed to do and this is born out by your gravity data.