This xBmt was completed by a member of The Brü Club as a part of The Brü Club xBmt Series in collaboration with Brülosophy. While members who choose to participate in this series generally take inspiration from Brülosophy, the bulk of design, writing, and editing is handled by members unless otherwise specified. Articles featured on Brulosophy.com are selected by The Brü Club leadership prior to being submitted for publication. Visit The Brü Club website for more information on this series.

Author: Richard Westmoreland

When homebrewers first step into the hobby, they’re typically encouraged to brew darker styles of beer, the general opinion seeming to be it’s easier to hide behind the character from roasted grains. While coffee and chocolate flavors can potentially cover up some off-flavors created at various stages of the brewing process, some say improper use of roasted grains can impart their own set of undesirable characteristics, particularly acrid, astringent, and burnt flavors.

What is the proper way to use roasted grains during the brewing process? After listening to an interview with Jennifer Talley on The Brewing Network’s Brew Strong podcast, I decided to give her technique of sprinkling the roasted malts on top of the mash bed before the sparge a try, which she claimed gives a smoother roast character without the acridness and astringency.

After brewing one Schwarzbier with this method that I ended up loving, I realized bias might be at play and felt I needed to put this in front of tasters in the form of a triangle test. Let’s get to it!

| PURPOSE |

To evaluate the differences between a Schwarzbier brewed with roasted grains included in the full mash and one where the roasted grains were added to the top of the mash at sparge.

| METHODS |

2018 was the year of German styles for me, and what better way to get me through the colder months than a nice, dark Schwarzbier. I also enjoy more sessionable beers, so I decided to test the impact of mashing roasted grains versus capping the mash before the sparge on a lower alcohol version of a German Schwarzbier.

Schwarzlicht

Recipe Details Batch Size Boil Time IBU SRM Est. OG Est. FG ABV 5.5 gal 90 min 23.0 IBUs 27.8 SRM 1.052 1.012 5.4 % Actuals 1.052 1.012 5.3 % Fermentables Name Amount % Pelton PIlsner 8 lbs 71.11 Metolius Munich 2 lbs 17.77 Carafa II (Weyermann) 11.99 oz 6.66 Caramel/Crystal Malt 8.01 oz 4.45 Hops Name Amount Time Use Form Alpha % Hallertauer 28.3 g 60 min Boil Pellet 4.8 Hallertauer 28.3 g 10 min Boil Pellet 4.8 Yeast Name Lab Attenuation Temperature Harvest (L17) Imperial Yeast 72% 64°F - 69°F Download Download this recipe's BeerXML file

My first order of business was purchasing the ingredients for both batches.

Since I only have one Robobrew electric rig, I brewed the two batches back-to-back, the first with entire grist mashed together while the second batch was mashed without the roasted grains, both at 149°F/65°C. The water for both batches was adjusted such that each would achieve the same 5.4 mash pH. After collecting the first runnings from the second batch, I sprinkled the finely ground roasted grains on top of the grainbed and began the sparge step.

Each batch was boiled for 90 minutes then chilled to 80°F/27°C before I took hydrometer measurements showing both were at the same OG.

Equal volumes of wort were transferred to identical PET carboys.

I placed foil atop each carboy and placed them in fermentation chambers, at which point I could already see a difference in color.

I let the worts chill overnight to my desired fermentation temperature of 50°F/10°C before pitching a pouch of Imperial Yeast L13 Global into each batch.

Signs of fermentation were evident in both batches 24 hours later. After a few days, I raised the temperature 60°F/16°C for a diacetyl rest and let them finish out. Hydrometer measurments taken 11 days later showed both beers finished at the same 1.012 FG.

After transferring the beers to kegs, they were burst carbonated and left to condition for a few days before I served them to tasters. Unfortunately, I forgot to get pictures of the finished beers. Suffice to say, there was a noticeable color difference between them, the full mash beer being darker and more opaque than the capped mash version.

| RESULTS |

A total of 18 people of varying levels of experience participated in this xBmt. Each participant was served 2 samples of the beer made with roasted grains included in teh full mash and 1 sample of the beer made with roasted grains added during the sparge in opaque cups then asked to identify the unique sample. While 10 tasters (p<0.05) would have had to accurately identify the unique sample in order to reach statistical significance, a total of 12 did so (p=0.004), suggesting participants in this xBmt were able to reliably distinguish a Schwarzbier mashed with roasted grains in the full mash from one where the roasted grains were added at the sparge step.

My Impressions: Out of the 5 semi-blind triangle tests I attempted, I accurately identified the unique sample every time. To me, the capped mash beer seemed drier and crisper with a more balanced roasted malt flavor than the full mash version. which I felt was too roasty for a Schwarzbier. Neither beer was bad, just different.

| DISCUSSION |

Roasted flavors including coffee and even slightly burnt toast are expected in certain styles of beer where good portions of darker malts are used. Unfortunately, the grains used to produce such styles can also impart acrid flavors that taste more like burnt ash than the clean roasted characteristics brewers are after. It’s been posited these generally undesirable flavors are a function of how long the roasted grains spend in the hot mash, with shorter contact time leading to less harshness. Seeing as the enzymes in roasted grains are denatured in the roasting process, they don’t require mashing, hence some brewers have taken to adding them toward the end of the mash rest or during the sparge step to reduce the risk of astringency. Indeed, participants in this xBmt were able to tell apart a Schwarzbier made with roasted grains in the full mash from one where the roasted grains were added just before sparging.

With these results corroborating those of a previous Brülosophy xBmt on the same subject, it would seem adding roasted grains at the vorlauf or sparge step really does lead to a perceptible difference. I didn’t gather data on what it was about the the beers that helped tasters distinguish them, but based on my own anecdotal experience, the capped mash version had a smoother roast character, which may or may not be preferred. In fact, while the softer roast worked great for a Schwarzbier, it’s possible employing this method on styles like Porter and Stout may lead to a less desirable outcome.

One thought I had when comparing these beers is whether other not I could achieve similar results by simply using less roasted grains in a full mash. Doing so would lead to less color, as observed in the capped mash beer, as well as less overall roast character, which could include astringency. While I plan to continue experimenting with this method, and despite having a slight preference for the capped mash beer in this xBmt, including all the grains in the full mash is easier on my system, so that’s the method I’ll be sticking with.

| About The Author |

Richard Westmoreland is a homebrewer from Houston, TX who got his start in 2015 with a 1 gallon extract kit. After his first batch, he was hooked and decided to dive headfirst into all grain brewing. Richard currently brews multiple batches per month on a Robobrew 3-in-1 electric system and is the inventor of the WiFerm Temperature Controller .

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