Author: Jordan Folks
Märzen is a classic German lager that’s noted for its amber to copper color, which traditionally was a function of the ingredients used to produce it, or more specifically, the way those grains were kilned. Given advancements in the malting industry, grains that impart the expected flavor profile of Märzen are often a bit paler than they were when the style was first being brewed, leading many modern brewers to rely on a dose of roasted grains to achieve the desired color.
A concern held by many Märzen brewers is ensuring their finished beer doesn’t possess any of the burnt or acrid characteristics associated with roasted grains. Of the handful of methods developed to combat this, capping the mash is a simple one that involves keeping the dark roasted grains out for the bulk of the mash, only adding them in during the last few minutes. In addition to lending color with minimal flavor contribution, this method also ensures the mash pH doesn’t drop too low from the presence of roasted grains.
The idea of capping the mash has been around for a long time, though it was the advice of Ashleigh Carter from Bierstadt Lagerhaus that led to me regularly employing this method when using roasted grains for color correction. While I’ve been pleased with how this method has worked in my brewing, I was curious what impact including the roasted grains in the full mash might have and designed an xBmt to see for myself.
| PURPOSE |
To evaluate the differences between a Märzen where Carafa Special III is added at the end of the mash rest and one where it’s included for the duration of the mash rest.
| METHODS |
With my annual Oktoberfest party on the horizon, I used my go-to house Märzen recipe for this xBmt. Big thanks to F.H. Steinbart for hooking me up with the malt for this batch!
Red Bird
Recipe Details
| Batch Size | Boil Time | IBU | SRM | Est. OG | Est. FG | ABV |
|---|---|---|---|---|---|---|
| 5.4 gal | 75 min | 29.7 | 13 SRM | 1.056 | 1.01 | 6.04 % |
| Actuals | 1.056 | 1.01 | 6.04 % | |||
Fermentables
| Name | Amount | % |
|---|---|---|
| Munich Malt | 5 lbs | 39.6 |
| Vienna Malt | 4 lbs | 31.68 |
| Pilsner Malt | 3 lbs | 23.76 |
| Carahell | 8 oz | 3.96 |
| Carafa Special III | 2 oz | 0.99 |
Hops
| Name | Amount | Time | Use | Form | Alpha % |
|---|---|---|---|---|---|
| Tettnanger | 57 g | 75 min | First Wort | Pellet | 2.7 |
| Hallertauer Mittelfrueh | 57 g | 60 min | Boil | Pellet | 2.9 |
Yeast
| Name | Lab | Attenuation | Temperature |
|---|---|---|---|
| Global (L13) | Imperial Yeast | 77% | 46°F - 55.9°F |
Notes
| Water Profile: Ca 74 | Mg 4 | Na 10 | SO4 91 | Cl 61 |
Download
| Download this recipe's BeerXML file |
After collecting the full volume of filtered tap water for two 5 gallon/19 liter batches, adjusting them to the same desired profile, and getting them heating up, I milled the grain, keeping the Carafa Special III out for one of the batches.
The mashes were initially held at 146°F/63°C for 60 minutes with pH readings taken toward the end that showed a very small, albeit expected, difference.
When the saccharification step was complete on each batch, the temperature was raised to 156°F/69°C for a mashout step, at which point the milled Carafa Special III was added to the experimental batch.
At this point, I weighed out the kettle hop additions.
Toward the end of the 20 minute mashout rest, I took another pH reading of the mash that I’d capped with Carafa Special III and found it now matched the other mash pH.
I proceeded to boil each wort for 60 minutes before quickly chilling them with my JaDeD Brewing SS Coil Hydra then taking refractometer readings indicating a slight difference in OG.
After transferring identical volumes of wort from each batch to separate fermentation kegs, I pitched equal amounts of Imperial Yeast L13 Global slurry into both.
The beers were left to ferment at 47°F/8°C for 2 weeks before I took hydrometer measurements showing the beers were at the same FG.
At this point, I gradually reduced the temperature of the beers to 32°F/0°C over the course of a few days then pressure-transferred each to CO2 purged serving kegs that were placed in my keezer. After a month of lagering, the beers were clear, carbonated, and ready for evaluation.
| RESULTS |
A total of 28 people of varying levels of experience participated in this xBmt. Each participant was served 2 samples of the beer where the Carafa Special III was included the full mash and 1 sample of the capped mash beer in different colored opaque cups then asked to identify the unique sample. While 15 tasters (p<0.05) would have had to accurately identify the unique sample in order to reach statistical significance, only 11 did (p=0.31), indicating participants in this xBmt were unable to reliably distinguish a Märzen where Carafa Special III was included for the duration of the mash rest from one where it was added at mashout.
My Impressions: Out of the 5 semi-blind triangle tests I attempted, I correctly identified the odd-beer-out twice. I perceived the aroma, flavor, and mouthfeel of these beers as being far too similar for me to distinguish, which was good because they were excellent examples of Märzen – light and refreshing with ample malt character and noble hop flavor.
| DISCUSSION |
While expected in styles like Porter and Stout, the flavors commonly associated with roasted grains are inappropriate in other styles, which poses an issue for brewers relying on these grains for color correction in more delicately flavored styles. Capping the mash is a method relied on by many brewers, as it’s purported to impart desired color without the roasted flavors. Interestingly, tasters in this xBmt were unable to reliably distinguish a Märzen where Carafa Special III was included for the duration of the mash rest from one where it was added at mashout.
Perhaps the most plausible explanation for this result is that Carafa Special III is a dehusked roasted grain, the intention being to reduce the contribution of burnt flavors to beer. It’s also possible that the 1% Carafa Special III used in this recipe simply isn’t enough to have a perceptible aroma and flavor impact, which is buttressed by the significant results from a past xBmt where roasted barley made up a larger portion of the grist. Moreover, the astringent qualities of roasted grains are said to be more prone to being extracted during a continuous sparge, which was not a method employed for the beers in this xBmt.
Bierstadt Lagerhaus makes incredible beer and hence I’m compelled to trust the advice of head brewer, Ashleigh Carter. However, when it comes to capping the mash, it seems reasonable that it has a more notable impact on larger batches brewed on commercial systems, which tend to rely on continuous sparging. Given how easy this method is to employ, I’ll continue to use it in cases where I want to keep the risk of roasted flavors as low as possible when using dark grains for color correction.
If you have any thoughts about this xBmt, please do not hesitate to share in the comments section below!
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