Author: Marshall Schott

Even before publishing the first boil length xBmt comparing a Pale Ale boiled for 60 vs. 30 minutes, and then failing at a second attempt, I’d been anticipating repeating it with a mostly Pilsner malt wort. I imagine most homebrewers have heard that longer boils drive off more DMS, the precursor of which (SMM) is more abundant in lower °L Pilsner malts. I’ve even heard of some people who boil for a minimum of 90 minutes for every batch, regardless of the base malt used, influenced at least to some degree by the fear of creating a beer that tastes like cooked cabbage or creamed corn.

I’ve always thought the way us humans deal with time is interesting, how we’ve imbued certain chunks of time with immense meaning, and this couldn’t be more prominent than it is in homebrewing– mash for 1 hour, boil for 60-90 minutes, rehydrate dry yeast for 15 minutes, ferment for 2 weeks, bottle condition for 3 weeks. Obviously, shit happens over time, I’m not saying this stuff doesn’t matter, but taking a huge step back, I can’t help but notice the absurdity of it all, how arbitrary it feels.

I fully understand there are those brewers out there who engage in particular practices purely as a function of their interest in said practice, despite evidence suggesting it likely makes little difference in the finished product. I truly appreciate and almost envy this mentality, though as I’ve made rather clear, I’m far more motivated by simplification and efficiency– if I can make in 3 hours a beer that’s equally as delicious as one that takes longer by modifying a few parts of my process, count me in!

| PURPOSE |

To evaluate the differences between a 30 minute boil and 90 minute boil in beers produced from the same mostly Pilsner malt grain bill and otherwise treated exactly the same.

| METHODS |

Hoping to avoiding the mess I ran into last time, I produced a large starter using a fresh vial of WLP029 German Ale/Kölsch yeast a couple days before brewing, it would be split between the 2 batches after I stole some for future use.

Similar to the latest sloppy old slurry xBmt, the recipe for this Kölsch was a product of the odd yet fun limitations of the BrewUnited Challenge.

BrewUnited Challenge Kölsch

Batch Size Boil Time IBU SRM OG FG ABV 5.5 gal 90/30 min 22 4.1 1.043 SG 1.010 SG 4.3%

Fermentables

Name Amount % German Pils Malt 8 lbs 8 oz 92.9 Gambrinus Munich 10 5 oz 3.4 Flaked Wheat Malt 4 oz 2.7 Crystal/Caramel 60 1.4 oz 1.0

Hops

Name Amt/IBU Time Use Form Alpha % Northern Brewer 27 g/20 IBU 30 Min Boil Pellet 10.1% Saaz 20 g/1.8 IBU 10 Min Boil Pellet 3.0%

Yeast

Name Lab Attenuation Ferm Temp WLP029 German Ale/Kölsch White Labs 029 83% 66°F

Water Profile

Ca Mg Na SO4 Cl HCO3 pH 64 ppm 0 ppm 10 ppm 56 ppm 71 ppm 33 ppm 5.3

For sanity’s sake, I usually stagger the start of each batch on dual-batch brew days by about 20 minutes, but because this xBmt had a 1 hour differential built-in, I hit the flame under both kettles of strike water simultaneously. The long-boil batch had 1 gallon more water and took about 6 minutes longer to heat, enough of a difference that I was able to begin collecting the sweet wort from each batch after both completed a 1 hour rest.

Both no sparge mashes ended up being just a hair north of my target rest temperature of 148°F, which was fine for me, so secured the lid and let them rest for an hour, briefly stirring every 15 minutes or so.

About 10 minutes in, I pulled a small sample to ensure a similar pH, as I’d used the Bru’n Water spreadsheet to adjust each batch based on their different liquor volumes. Not too shabby!

The timer for short-boil batch went off after an hour and I began collecting the sweet wort, which I finished just as the timer for the long-boil batch began to ding. The worts were collected in a bucket and transferred to separate kettles.

My boiloff rate currently hovers around 1 gallon per hous, thus the short-boil batch had approximately 1 gallon less sweet wort in the kettle than the long-boil batch. I added the first charge of Northern Brewer hops at 30 minutes and a later addition of Saaz was tossed in prior to chilling.

Once the boils were complete, I was pleased to find each wort shared a similar OG, with the short-boil batch clocking in at 1.044 while the long-boil batch ended up at a slightly higher 1.046. Separate 6 gallon PET carboys were filled, labeled, and placed in my chamber to finish chilling to my target fermentation temperature of 66°F. After about 4 hours, I returned and pitched equal amounts of starter slurry into each fermentor. It didn’t take long for signs of active fermentation to arrive.

Fermentation progressed similarly for both beers. My Black Box temp controller began ramping temps up after 3 days, eventually stopping at 72°F where it remained for a couple more days. It was at this point I took an initial hydrometer reading, which was followed by a confirmatory measurement 2 days later.

It wouldn’t have surprised me to discover the beers finished at different SGs, though I thought it was curious the lower OG short-boil beer had a slightly higher FG than the long-boil batch. Still, close enough. I proceeded to crash the beers, fine them with gelatin, and rack them to kegs.

After sitting on 40 psi of CO2 for 24 hours, I reduced the pressure to 14 psi and left them alone another 4 days before presenting the beers to participants. Both were nicely carbonated and clear by this point, and as I’d noticed during both hydrometer measurements, the short-boil beer was ever-so-slightly lighter than the long-boil beer.

| RESULTS |

Data for this xBmt was collected over 6 days and included a panel of 18 participants from various backgrounds ranging from BJCP judges, experienced homebrewers, and dedicated craft beer junkies. Each participant was served 3 samples in separate colored opaque cups, 1 from the long-boil batch and 2 from the short-boil batch. In order to achieve statistical significance with the given sample size, 10 tasters (p<0.05) would be required to accurately identify the long-boil beer as being unique. Of the 18 participants, only 6 (p=0.50) made the accurate selection in the triangle test, a response rate consistent with chance, indicating a demonstrable inability to reliably distinguish a mostly Pilsner malt based beer boiled for 90 minutes from one boiled for only 30 minutes.

While the comparative evaluations of those participants who did accurately identify the odd-beer-out are inconsistent and generally meaningless, I think it’s prudent to note not a single person reported perceiving anything close to DMS in either beer and, in fact, both were equally well received.

My Impressions: From the first hydrometer readings to my final comparison, there was one difference between these beers that was very obvious to me– color. The long-boil batch was noticeably, though not all too obviously, darker than its short-boil counterpart, which I expected and assumed would produce a perceptible difference. Nope. In no way was I capable of telling these beers apart in a reliable manner, regardless of my sampling method. Both have a nice bread crust character from the Best Malz Pilsner malt balanced by a soft spicy Saaz note and, interestingly, a slight murmur of cotton candy, which I believe is a result of the 1% C60 I was forced to use. All in all, I think this beer may fare well in the BrewUnited competition, into which I plan to enter the short-boil version, though I’ve no plans to brew it again.

| DISCUSSION |

It’s been awhile since the negative results of an xBmt have really surprised me, shaken the core of what I’ve accepted as brewing truth. This one sort of did. It’s weird because a part of me expected these results, though a larger part hoped for significance, mostly for self-validating reasons– I’ve a history of advocating for 90 minute boils in mostly Pilsner malt based worts. While I’ve neither the equipment nor the intelligence to be able to objectively measure differences in beer composition, I can’t help but wonder if the long-boil batch actually contained less DMS than the short-boil, perhaps just below the threshold of perception. I’m compelled to believe this is likely true, though my belief is admittedly motivated by my own appeal to authority. Moreover, I wonder the extent to which boil volume plays a role. Since evaporation rates are generally fairly constant and not linearly related to volume, it stands to reason less DMS would be driven off during the boil thereby increasing the risk of DMS in the finished beer. Given our propensity as homebrewers to accept professional brewing practices as the gold standard, it seems wholly possible the conventional wisdom regarding boil lengths stems from experiences and research that don’t necessarily apply on our smaller scale.

In most of these discussions, we try to comment on how the results will impact our brewing, and nearly every time we’ve said it likely won’t. Even with the scarcity of good evidence, my obsession with efficiency combined with my experience with these (and a couple other) short-boiled beers is winning out, I absolutely plan reduce my typical boil times. However, this isn’t something I’m ready to recommend for anyone else, I rather enjoy the risks involved with process tweaks like this. For those who are interested, keep in mind you will need to use more and/or higher AA% hops to achieve your target IBU, and your paler short-boiled beers will likely be a touch lighter than expected.

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