exBEERiment | Mash Temperature: Low vs. High In A German Helles Exportbier

Author: Will Lovell

Brewers have several proverbial knobs they can turn to determine the ultimate character of the beer they’re making, one of which is mash temperature. Despite the acceptable mash temperature range being relatively small, differences of just a few degrees will have a measurable impact on residual sugars, leading many to view it as a way to control dryness and sweetness.

Whereas warmer mashes activate alpha-amylase enzymes that leave more unfermentable sugars in the wort, cooler mashes activate beta-amylase enzymes that do the opposite, resulting in a more fermentable wort. As such, a brewer looking to enhance the sweetness of, say, a Porter may opt to mash at 160°F/71°C while they might go with 149°F/65°C for a crisp, dry Pilsner.

Over the years, we’ve performed several xBmts on mash temperature, and the results have been surprising, to say the least. What I recently realized is that the four focused on lagers all looked at fairly low ABV styles. I was curious what effect different mash temperatures might have in a slightly higher strength pale lager and designed an xBmt to see for myself.

| PURPOSE |

To evaluate the differences between a Helles Bock mashed cool (153°F/67°C) and one mashed warm (164°F/73°C).

| METHODS |

Given the purpose of this xBmt, I thought a simple Helles Bock recipe would work nicely.

The Bockman Cometh

After adding identical volumes of water to separate Delta Brewing AIO units, adjusting each to the same mineral profile, and milling the separate sets of grain, I set each electric controller to their specific strike temperatures. Once reached, I mashed in and set one controller to 152°F/67°C while the other was set to 163°F/73°C.

While the mashes were resting, I prepared the kettle hop additions.

Once each 60 minute mash rests were complete, the worts were boiled for 60 minutes, after which they were quickly chilled before I took refractometer readings showing they were at the same target OG.

I transferred identical volumes of wort from each batch to Delta Brewing FermTanks that were attached to my glycol system and left to finish chilling to my desired fermentation temperature. When the worts were stabilized at 66°F/19°C, I pitched a sachet of Fermentis Saflager W-34/70 into each.

With signs of activity absent 8 days later, I took hydrometer measurements showing a relatively vast difference in FG, which was to be expected.

At this point, I cold crashed the beers overnight before pressure transferring them to CO2 purged serving kegs that were placed on gas in my keezer. After 2 weeks of cold conditioning, they were carbonated and ready to serve to tasters, despite maintaining a notable chill haze.

| RESULTS |

A total of 13 people of varying levels of experience participated in this xBmt. Each participant was served 1 sample of the beer mashed cool and 2 samples of the beer mashed warm in different colored opaque cups then asked to identify the unique sample. In order to reach statistical significance, 8 tasters (p<0.05) would have had to accurately identify the unique sample, and 9 did (p=0.009), indicating participants in this xBmt were able to reliably distinguish a German Helles Exportbier mashed cool at 153°F/67°C from one mashed warm at 164°F/73°C.

The 9 participants who made the accurate selection on the triangle test were instructed to complete a brief preference survey comparing only the beers that were different. A total of 5 tasters reported preferring the beer mashed cool, 3 said they liked the beer mashed warm, and 1 had no preference despite perceiving a difference.

My Impressions: Out of the 5 semi-blind triangle tests I attempted, I correctly identified the odd-beer-out 4 times. I perceived a light sulfur note in the warm mashed beer that was absent in the one mashed cooler, which came across cleaner and crisper by comparison. Given the choice, I’d go with the low mash temperature version, though neither was necessarily unpleasant.

| DISCUSSION |

Mash temperature is often treated as a dependable way to steer a beer’s body and attenuation, with warmer mashes conventionally expected to leave more residual sweetness and cooler mashes expected to finish drier and crisper. The fact tasters in this xBmt were able to reliably distinguish a German Helles Exportbier mashed cool from one mashed warm lends some support to that conventional thinking.

This result stands somewhat apart from several of our past mash temperature xBmts, most of which failed to turn up a reliably perceptible difference, though those were largely lower gravity styles. It’s possible the higher strength and maltier profile of this German Helles Exportbier made fermentability differences easier to pick out, though the light sulfur character noted in the higher-temp sample also raises the possibility that fermentation-related factors, perhaps as a function of mash temperature, contributed to what tasters perceived.

Having gone in expecting another instance of mash temperature not translating to the glass, based on how so many of our past xBmts on this variable have gone, I was a bit surprised with not only the blind taster results, but my own ability to tell them apart as well. This has left me even more curious of the impact mash temperature has on the perceptible qualities of beer, particularly as it relates to fermentation quality, as none of the tasters made any mention of sweetness as being a factor. At this point, I’m wont to continue viewing mash temperature as lever to adjust ABV rather than sweetness, but I’m open to changing that stance and look forward to further exploring this quintessential brewing variable.

If you have any thoughts about this xBmt, please do not hesitate to share in the comments section below!

Support Brülosophy In Style!

Follow Brülosophy on:

FACEBOOK   |   TWITTER   |   INSTAGRAM

If you enjoy this stuff and feel compelled to support Brulosophy.com, please check out the Support page for details on how you can very easily do so. Thanks!