Author: Steve Thanos
The mash is an essential part of the brewing process where milled grains are steeped in hot water, which activates enzymes that convert starch from the malt into fermentable sugar. Over the course of brewing history, it’s become customary to mash for 60 minutes, as this allows enough time for complete conversion. Recent evidence suggests abbreviated mash rests, while sufficient, tend to result in slightly lower conversion efficiency, but much less is known about the impact of lengthened mash rests.
While continued enzymatic conversion may be a positive associated with extended mash rests, one consideration has to do with mash temperature consistency, which can be difficult to maintain on certain brewing systems. As annoying as this can be, the results of various xBmts showing that fairly large differences in mash temperature doesn’t seem to have much of a perceptible impact provides some solace.
Brewing beer is a relatively time-intensive process, and as a hobbyist who has other responsibilities, there a number things that can interrupt a typical brew day, like having to drop my kid off at their friend’s house or making sure to clean up the empty beer cans from the spur of the moment party I threw a couple nights prior. Short & Shoddy brewing is certainly one way around these hurdles, but when I’m not feeling up for a hectic brew day, extending certain processes would be very helpful, so long as I’m confident it doesn’t impact the quality of my beer. It’s this that motivated me to design an xBmt testing out the impact of extending the mash rest beyond what is accepted as “normal.”
| PURPOSE |
To evaluate the differences between an American Brown Ale that was mashed for 1 hour and one that was mashed for 2 hours.
| METHODS |
For this xBmt, I went with a simple American Brown Ale recipe that has enough specialty grains to keep things interesting.
Banned Words
Recipe Details
| Batch Size | Boil Time | IBU | SRM | Est. OG | Est. FG | ABV |
|---|---|---|---|---|---|---|
| 5.5 gal | 60 min | 34.9 | 31.2 SRM | 1.051 | 1.012 | 5.12 % |
| Actuals | 1.051 | 1.012 | 5.12 % | |||
Fermentables
| Name | Amount | % |
|---|---|---|
| Vienna | 8 lbs | 82.05 |
| Chocolate | 12 oz | 7.69 |
| Biscuit | 8 oz | 5.13 |
| Caramel Malt 120L | 8 oz | 5.13 |
Hops
| Name | Amount | Time | Use | Form | Alpha % |
|---|---|---|---|---|---|
| Pekko | 10 g | 60 min | Boil | Pellet | 18.5 |
| Pekko | 28 g | 5 min | Boil | Pellet | 18.5 |
Yeast
| Name | Lab | Attenuation | Temperature |
|---|---|---|---|
| Independence (A15) | Imperial Yeast | 76% | 0°F - 0°F |
Notes
| Water Profile: Ca 55 l Mg 12 l Na 9 l SO4 48 l Cl 35 |
Download
| Download this recipe's BeerXML file |
After collecting 2 sets of water and lighting the flame to get them heating up, I weighed out and milled the grains.
Once the water for each batch was adequately heated, I incorporated the grains then checked to make sure both were at the same target mash temperature.
While the mashes were resting, I prepared the kettle hop additions.
After 60 minutes, I removed the grains from one batch, then left the other batch alone for an additional 60 minutes before removing the grains from it. Both worts were then boiled for 1 hour before being chilled with my JaDeD Brewing Hydra IC.
Hydrometer measurments showed the wort from the 1 hour mash had a slightly higher OG than the wort from the 2 hour mash, which was unexpected.
The filled fermenters were placed in my chamber and left to finish chilling to my desired fermentation temperature of 66°F/19°C for a few hours before I pitched a pouch of Imperial Yeast A15 Independence into each.
With signs of fermentation activity absent after 3 weeks, I took hydrometer measurements showing the beers had reached the same FG.
I then pressure transferred the beers to separate kegs and placed them in my keezer where they were left to condition for a week before they were ready to serve.
| RESULTS |
Cheers to Werk Force Brewing allowing me to collect data at their killer establishment. A total of 20 people of varying levels of experience participated in this xBmt. Each participant was served 2 samples of the beer mashed for 1 hour and 1 sample of the beer mashed for 2 hours in different colored opaque cups then asked to identify the unique sample. In order to reach statistical significance, 11 tasters (p<0.05) would have had to accurately identify the unique sample, which is exactly the number that did (p=0.038), indicating participants in this xBmt were able to reliably distinguish an American Brown Ale mashed for 1 hour from one that was mashed for 2 hours.
The 11 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 for 1 hour, 3 said they liked the beer mashed for 2 hours more, and 3 reported perceiving no difference.
My Impressions: Out of the 5 semi-blind triangle tests I attempted, I correctly identified the odd-beer-out just 2 times, indicating my inability to consistently distinguish them. To my palate, these beers were identical, both possessing a pleasant blend of toasty, chocolate, and light caramel notes with hints of supportive non-descript hops and clean fermentation character.
| DISCUSSION |
Sweet wort is produced during the mash, a process where enzymes convert the starches from grains into fermentable sugar. Seeing as this does not occur immediately, it’s commonly recommended to mash for 60 minutes, though some opt to go even longer to either encourage more conversion or make for a more convenient brew day. Interestingly, tasters in this xBmt were able to reliably distinguish an American Brown Ale mashed for 1 hour from one that was mashed for 2 hours.
In considering explanations for this result, especially given tasters in a past xBmt were unable to distinguish a beer mashed overnight from one mashed for an hour, a couple possibilities came to mind. First, it could be that beers with more complex grain bills react differently to longer mash rests than simpler grain bills. Then again, with 3 tasters who happened to be right on the triangle test reporting they perceived no difference between the beers, there’s at least some chance these results are a false positive. Obviously, that cannot be determined based on this single finding, so future mash length xBmts are certainly in order.
Having completed my own series of triangle tests prior to analyzing the blind taster data, I admittedly expected the results to align with my experience, but that wasn’t the case. To me, these beers were identical, and seeing as I’ve been pleased with past batches where I extended the mash, I’ll have no problems doing it again when needed, at least until we get more evidence showing it has some detrimental impact.
If you have any thoughts about this xBmt, please do not hesitate to share in the comments section below!
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9 thoughts on “exBEERiment | Impact Mash Length Has On An American Brown Ale”
I’d go with your experience of the two beers. I find it higly likey that this is, as you’re suggesting, a false positive.
As for the OG measurements: Isn’t the difference accountable for by the bubbles clinging to the stem of the hydrometer on the left? I can’t think of any reason why you might get a lower OG by mashing longer – if you do everything right, that is.
11 correct out of 20 is not much of a test. I still say that 3 or 4 of the 11 were simply lucky guesses. Try running the test again with the same people and see if they still make the same lucky guesses.
Thanks for another informative exBeeriment. “3 reported perceiving no difference” yet, they said they did because they picked one over the other. Obviously, this is guessing. Throw it out and the “p” factor fails. Your personal tests confirm this. There are previous tests that confirm this. More tests needed? Nah. It’s clear. Brülosophy has repeatedly demonstrated hobby brewing has far more flexibility than the usual literature portrays. We are not commercial enterprises that have staked their success on repeating the same flavor profile decade after decade. Even with this recipes have changed. My own brewing experience with Brülosophy’s results has taught me this. So, thanks for aiding me in relaxing my brew days, yet still within the general parameters.
You can’t throw out guesses. In fact, triangle tests are used specifically because they account for guessing and random chance.
https://www.sensorysociety.org/knowledge/sspwiki/Pages/Triangle%20Test.aspx
I was hoping that one of the options would have been a short and shoddy – I adjusted my brown ale recipe to a 30 min mash and no one could taste the difference.
I will have to try that! I’ve reduced my boil to 30 minutes with no detectable differences. I’d love to cut another 30 minutes of my brew day!
Interesting, but I wonder if this didn’t actually test what you though. It doesn’t sound like you performed a mash-out on the “60-minute” batch. So any enzymes that were dissolved into the wort were still present, and still active. Sure you removed the grains, but probably everything soluble in the grains was already dissolved after 60 minutes anyway.
So this seems to have been a test comparing two 120 minute mashes, where one had the grains removed halfway through. Instead of a 60 minute mash compared to a 120 minute mash.
The higher gravity in the removed-grain batch is interesting. Maybe pulling out the grains let it cool down a bit and that had an effect?
I’d love to see a repeat of this with a mash rest (or going right to the boil) after 60 minutes to deactivate enzymes.
Thanks for the great work you all do! Love reading these twice a week.
This is interesting, I normally mash for one hour, but lately I have continued the mash until complete conversion (starch test) which is often as long as 90 minutes. And often raising the mash temp to reach full conversion. I find no difference in taste, but usually I do get a slightly better efficiency; this can be as much as 3%. What I do find is I get better overall mouthfeel in beers that have a good extraction rate.
Never thought about how the complexity of the grain bills would react to longer mash rests, very interesting