Effects of Maltotriose Yeast
METHODS MADE SIMPLE | Effects of Maltotriose yeast
Quite often we hear from some experts, and we recommend ourselves the use of maltotriose negative yeasts or other low attenuating strains, but how much difference does it contribute to NA/LA brewing? Maltotriose is a complex malt sugar, most brewer’s yeasts can metabolize maltotriose effectively, but only after all the simpler sugars, such as glucose, fructose, sucrose, and maltose have been consumed. But there are some strains lack the ability to convert this sugar such as Lallemand Windsor and London Ale III, resulting in a lower attenuation leaving behind residual sweetness, body, and mouthfeel.
So, what does this mean to me? As a brewer of non-alcoholic beer, lower attenuation and residual body/sweetness is something I desire in my fermentation, it leaves me with a more rounded fuller beer. But how much difference does it have compared to a regular yeast strain? Starting with a low original gravity wort consisting of mainly long chain sugars means I’m only getting a very brief ferment, so will this make much of a difference? We put it to the test.
Impact of Maltotriose Yeast
In this experiment, we will be looking to compare how much an impact the use of a maltotriose negative strain (Lallemand Windsor) has compared to a regular strain (Lallemand Verdant IPA). We will be looking to see if by using this style of yeast, we can create a beer with lower attenuation and a fuller body, resulting in a better tasting non-alcoholic beer.
By brewing a 22-litre batch of a hop forward Pale Ale, it will then be split into two 11 litre batches, both pitched with a different strain, left to ferment, cold crash, and carbonate before comparing results in a triangle test to determine if the yeast made an impact.
“Another Pale Ale”
Batch size: 22 L
| MASH TIME | BOIL TIME | IBU | EBC | EST. OG | EST. FG | ABV |
| 30 mins | 30 mins | 34.0 | 7.9 EBC | 1.013 | 1.010 | 0.40 % |
| Actuals | 1.014 | 1.008 (Ver) 1.010 (Win) | 0.50 % 0.80% | |||
Grain Bill
| NAME | AMOUNT | % |
| JWM Munich Light | 800g | 35.6 |
| Simpsons Maris Otter | 710g | 31.6 |
| Weyermann Carapils | 327g | 14.6 |
| Gladfield Toffee | 230g | 10.2 |
| Blue Lake Maltings Flaked Barley | 180g | 8.0 |
Hop Schedule
| NAME | AMOUNT | TIME | USE | FORM | ALPHA % |
| Warrior | 12g | 30 min | Boil | Pellet | 15.1 |
| Amarillo | 20g | 5 min | Boil | Pellet | 8.6 |
| Talus | 25g | 5 min | Boil | Pellet | 8.9 |
| Amarillo | 50g | 4 days | Dry Hop | Pellet | 8.6 |
| Talus | 50g | 4 days | Dry Hop | Pellet | 8.9 |
Yeast
| NAME | LAB | ATTENUATION | TEMPERATURE |
| Verdant IPA | Lallemand | 25% (Est.) | 19°C |
| Windsor | Lallemand | 23% (Est.) | 19°C |
Other
| NAME | Amount | Time | Use |
| Whirlfloc | 1 Tablet | 10 mins | Clarity Agent |
| Water Profile: Ca2+ 96 | Mg2+ 12 | Na+ 27 | Cl⁻ 87 | SO₄²⁻ 162 | HCO₃⁻ 65 |
To start off with, we collect 28ltrs of our RO water, then fill our kettle and bring the water up to our strike temperature of 82ºC (179ºF). Once we reach our strike temperature, our water adjustments and our grain are added and stirred in to ensure we have no dough balls, then left to mash for 30 minutes at 80ºC (176ºF).
Once the mash is complete, we remove and drain the remaining wort from the bag, we then check our pre-boil gravity and proceed with the boil.
Once the wort has reached a boil, we start the timer for 30 minutes and add our first hop additions, continuing our way through the hop schedule and the addition of Whirlfloc.
Once the boil is complete, we take a sample to measure our post-boil gravity before transferring 11ltrs of the hot wort into each of the two separate HDPE cubes, pre-acidified to <4.6pH, and left cool down to pitching temperature overnight.
Once the wort has cooled overnight, we then pitch 5.5g of Lallemand Windsor into one of the cubes, and 5.5g of Lallemand Verdant IPA into the other cube and left to ferment for 7 days at 19ºC (66ºF), on day 3 we add our dry hop additions, and leave for the remainder of time.
After the 7 days have elapsed, we check to ensure we’ve reached terminal gravity, then cold crash both cubes for 3 days at 2ºC (35.6ºF), then transfer both beers to 9.5L kegs each and carbonated at 12 psi for 7 days before sampling.
Left: Verdant Batch
RESULTS
- Windsor: SG: 1.014, FG: 1.010, = 0.5% ABV
- Verdant: SG: 1.014, FG: 1.008 = 0.8% ABV
Appearance:
Both have a lovely golden glow, with a nice clear haze. Beautiful foam upon pours with a lasting sticky foam.
Aroma:
Juicy, tropical aroma, grapefruit, orange, with candy melon, light toffee/caramel aroma
Taste:
Delicate background caramel and toffee malt flavours, smooth piney/apple stalk bitterness up front along with a mouthful of tropical flavours including a prominent grapefruit and orange flavour, with a slight candy melon flavour, then a nice dry bitterness on the back end to entice another sip.
Overall First Impressions:
This is a very nice example of an American Pale Ale without the alcohol, with a great balance of flavours and aromas, and a lovely bright clear haze among a golden honey like colour. This certainly gets two thumbs up from me!
Side by side, both of these beers are very similar in all aspects. The Windsor stopped a couple gravity points higher at 1.010, with the Verdant batch falling lower to 1.008 and tipping just over the <0.5% category at 0.8% abv. I wasn’t surprised by these results, as I did expect to see a difference in fermentation and final gravity as the Windsor is a Maltotriose negative yeast, meaning it should have finished higher than Verdant, but without a side-by-side comparison, the actual difference wasn’t known.
To achieve a great tasting NA beer, we often suggest the use of Lallemand’s Windsor strain. It is certainly a great yeast to utilise in these processes, being maltotriose negative, this means it will leave behind some residual sugars, creating a lower abv and slightly sweeter/fuller beer than a standard yeast variety as we can see from the results of this experiment. If a brewer was still working their way through the motions of learning to brew an ultra-low/no alcohol beer, this would be a great place to start while they work out flavour combinations and fermentability control.
I do find the Windsor batch to be a slight bit softer and sweeter, whereas the Verdant is slightly drier and slightly more bitter and truer to style. I feel that going forward from these results from a finished beer perspective, I personally would be more inclined to use Verdant for my high hopped ales (IPA, APA etc.), I’d also be more inclined to adjust the batch to have a lower starting gravity to create a lower abv (<0.5% abv), as that batch seemed truer to style with more clearer flavours and finish, I felt as though Windsor softened up the flavours a bit more than I’d have liked even though they are very similar in every aspect.
Both are great beers, and if I didn’t have any Verdant, I’d happily use Windsor in place to save a trip to the LHBS.