The Impact of Glycerine in Beer
METHODS MADE SIMPLE | Impact of Glycerine in Beer
If you’ve dived into researching the effects of yeast, and the by-products they create during fermentation, you will be familiar things such as esters, phenols, diacetyl, and acetaldehyde to name a few, but one compound not often spoken about in beer brewing is glycerol. In the wine industry, glycerol is often a by-product that is highly desired by many winemakers to increase body and mouthfeel of wines, especially lower alcohol, or light wines, but what is it?
Glycerol, as it’s known in its concentrated form is commercially available as the dilute version known as glycerine. It is a naturally occurring sugar alcohol, it is an odourless liquid that is used as a solvent, a sweetening agent in food and beverages, and as a common additive in medicines and cosmetics. Glycerol also has a caloric density similar to table sugar, without the plaque and cavity causing side effects. Though many brewers would know it primarily as a cryoprotectant where the glycerol (or glycerine) is dissolved in water to reduce damage by ice crystals to laboratory organisms that are stored in frozen solutions, such as harvested yeast for a brewhouse yeast bank.
A recent article I recently uncovered mentions that the glycerol content of beer varies little — generally from 1100 to 2100 mg/l (Nykänen & Suomalainen, 1983), although Drawert et al. (1976) found average glycerol contents ranging up to 3170 mg/l in some German beers (Ref. 1.0). With the low rate of fermentation in low and no alcohol beer, a decrease in yeast by-products is inherit. This means a decrease in glycerol can be shown by a lack of potential body and mouthfeel, which got me interested in the idea of experimenting with dosing some of my beers, along with a commercial NA lager with some glycerine to determine to effects of this compound, and how much of a difference it could make. Previous to this experiment, I had dosed my beer glasses with unmeasured quantities in some of my other beers to some success, in this experiment I make a more documented and measured assessment.
Impact of Glycerine in the Finished Beer
For this experiment, I chose 3 different styles of beer with different ABV levels to assess the impact different dosage rates of glycerine has on different alcohol contents and flavours of beers. One being a commercial lager, and the other two being my own homebrewed beer, a stout, and an English IPA. The glycerine I purchased has a usage quantity of 3-5ml/L and is often used for distilling and/or wine making.
Process
I set out 4 sampling cups for each style of beer, I filled 1 with a sample of the beer to get a baseline of the flavour and body, and the remaining 3 cups got dosed with varying amounts of glycerine, then each topped up with the specific beer style to the 100ml mark for an equal evaluation of 0.2ml/100ml, 0.5ml/100ml, and 1.0ml/100ml.
The tasting was conducted in the same manner for each style of beer. The baseline beer was sampled initially, and between each dosed sample to get an evaluation of the prescribed quantity of glycerine. Then comparing each dosed quantity with each other to determine the best result.
Results
Three different beers and three ABV levels meant a lot of samples. I chose a commercial Lager that was listed as 0.5% abv, a homebrewed stout that was brewed to 0.3% abv, and an English IPA that was brewed to 1.7%.
(Commercial) Lager 0.5% abv
– 0.0ml (Base)
Low-medium body and mouthfeel, low level of sweetness in line with style.
– 0.2ml/100ml
Slight increase in body and mouthfeel, similar sweetness to base sample.
– 0.5ml/100ml
Large increase in body/mouthfeel, slight increase in sweetness on the aftertaste.
– 1.0ml/100ml
Big increase in mouthfeel and body, but also a large increase in a sweet syrup after-taste.
Overall:
Between 0.2 and 0.5ml/100ml would be an ideal dosage, I believe 0.30-0.35ml/100ml would be an ideal dose for this light style to imitate a full bodied beer.
(Homebrew) Stout 0.3% abv
– 0.0ml (Base)
Medium body and mouthfeel, low level of sweetness in line with style.
– 0.2ml/100ml
Slight increase in body and mouthfeel, similar sweetness to base sample.
– 0.5ml/100ml
Notable increase in body/mouthfeel, slight increase in sweetness on the aftertaste.
– 1.0ml/100ml
Big increase in mouthfeel and body, but also an increase in an artificial sweet syrup after-taste.
Overall:
Between 0.2 and 0.5ml/100ml would be an ideal dosage, I believe 0.3-0.35ml/100ml would be an ideal dose for this dark style with heavy roast flavours to imitate a full bodied beer.
(Homebrew) English IPA 1.7% abv
– 0.0ml (Base)
Medium-full body and mouthfeel, low-medium level of sweetness in line with style.
– 0.2ml/100ml
Slight increase in body and mouthfeel, similar sweetness to base sample.
– 0.5ml/100ml
Large increase in body/mouthfeel, slight increase in sweetness on the aftertaste.
– 1.0ml/100ml
Big increase in mouthfeel and body, but also an increase in an artificial sweet syrup after-taste.
Overall:
Between 0.2 and 0.5ml/100ml would be an ideal dosage, I believe 0.3-0.35ml/100ml would be an ideal dose for this crystal heavy style to imitate a full bodied beer.
After sampling each cup and gathering my test results, I conceded to the fact that despite a large difference in flavours between each of the 3 beers, they all showed the same or a similar result in the rates of glycerine mixed into the samples. Knowing 1.0ml/100ml would be way above an acceptable level, it was still used as a tolerance test to understand the effect of “how much is too much”. The consensus between each style was that 0.2ml/100ml had a slight increase in mouthfeel and body without a noticeable increase of sweetness, whereas the 0.5ml/100ml sample had a substantial increase in mouthfeel and body with a slight increase in sweetness. This drew me to the conclusion that a dosage rate between 0.3-0.35ml/100ml (3-3.5ml/L) would be an ideal quantity to add to the finished beer to increase the texture, and to give the perception of a full bodied beer with increased mouthfeel without increasing the perception of sweetness beyond the style.
The only drawback to adding extra glycerine to the beer would be an increase in calories, which can sometimes be an unwanted addition for some brewers looking for a healthy alternative. With most low and no alcohol beer being a style that is already low in calories (due to the lack of alcohol), we can turn a blind eye to this slight increase as a positive trade-off for what could be a better beer.