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: Cade Jobe

Like many homebrewers, the first beer I brewed used dry yeast from an unmarked package that I sprinkled directly into the fermentor. The beer was drinkable (Holy chemistry, Batman. I just made beer!), but nowhere near great. What could I do next time to make it better? Looking back now, 6 years after I brewed that first beer, that question feels like Morpheus’ red pill/blue pill dilemma: Should I just accept my “okay” beer or should I see how deep the rabbit hole goes?

Red pill. Every time.

Plenty of brewing texts offer tips, tricks and alleged solutions for making better beer. I’d read over and over again that dry yeast should always be rehydrated before pitching. According to the texts, yeast cell walls that get altered during the yeast drying process could be damaged—sometimes lethally—when direct pitched into unfermented wort. To avoid that, they suggest to gently rehydrate the yeast before pitching. The first paragraph to Lallemand’s recommended rehydration procedure says as much:

Rehydration is a crucial step to ensure rapid and complete fermentation. There are important rules to follow to slowly transition the cells back to a liquid phase. Careful precautions were taken when drying the yeast and the brewer has the opportunity to revert the process to obtain a highly viable and vital liquid slurry.

Lallemand goes on to report a list of issues observed when non-rehydrated yeast was used under certain brewing conditions:

Longer diacetyl stand

Longer fermentation time

Longer lag phase

Stuck fermentation

Poor utilization of maltotriose

For these reasons, I used rehydrated yeast in my next few batches with seemingly better results. Later, I went on to use liquid yeast and eventually starters, but I always wondered whether that rehydration step was really necessary.

It’s been 4 years and 208 xBmts since Marshall put rehydrated versus direct pitch yeast to the test, which did not reach a significant result. In this replication xBmt, I set out to brew the same beer following the same procedures as Marshall did the first time around.

| PURPOSE |

To evaluate the differences between a beer fermented with dry yeast pitched directly into the wort and one where the yeast was rehydrated first.

| METHODS |

The recipe for this xBmt was taken from Marshall’s previous xBmt on the same variable with changes made to accommodate for available ingredients and brewhouse efficiency.

Darktoberfest

Recipe Details Batch Size Boil Time IBU SRM Est. OG Est. FG ABV 5.5 gal 60 min 23.0 IBUs 15.2 SRM 1.051 1.012 5.1 % Actuals 1.051 1.012 5.1 % Fermentables Name Amount % Munich Malt - 10L 7.25 lbs 68.24 Pilsner (2 Row) Ger 3 lbs 28.24 Carafa II 4 oz 2.35 Melanoiden Malt 2 oz 1.18 Hops Name Amount Time Use Form Alpha % Hallertauer Mittelfrueh 28 g 60 min First Wort Pellet 4 Hallertauer Mittelfrueh 14 g 20 min Boil Pellet 4 Hallertauer Mittelfrueh 14 g 5 min Boil Pellet 4 Yeast Name Lab Attenuation Temperature Nottingham (-) Danstar 75% 57°F - 70°F Notes Water Profile : Ca 51 | Mg 21 | Na 38 | SO4 52 | 56 Download Download this recipe's BeerXML file

I started my #BruDay by collecting the brewing water and adjusting it to my desired profile.

As the water heated, I weighed out and milled the grains. Once the water hit strike temperature, I mashed in and checked to make sure I hit my intended mash temperature.

I grabbed a sample of wort about 15 minutes into the mash to check pH.

With the 60 minute mash complete, I performed my standard fly sparge process.

The wort was transferred into my kettle and the first wort hop addition was immediately added.

The wort was boiled for an hour with hops added per the recipe.

Using my custom JaDeD Brewing immersion chiller, I chilled the wort to a few degrees above groundwater temperature.

The chilled wort was then split between two identical Ss Brewtech Brew Buckets and set in my fermentation chamber to finish cooling to pitching temperature. A hydrometer measurement showed the wort had reached my intended OG.

Once the worts were adequately chilled, I rehydrated 1 packet of Nottingham yeast according to the manufacturer’s instructions.

I stirred the rehydrated yeast after 15 minutes and left it for another 5 minutes before pitching the entire slurry into one batch of wort. I then pitched 1 package of Nottingham dry yeast directly into the other wort. Blowoff tubes were attached to both fermentors and they were left alone.

Interested to see if there were noticeable differences during fermentation between the batches, I checked on them 14 hours later and noticed more kräusen formation in the beer pitched with rehydrated yeast.

However, after a full 24 hours, both batches were fermenting vigorously based on airlock activity. I let the beers ferment at 58°F/14°C for 15 days before taking hydrometer measurements confirming both had reached the same FG.

I then pressure transferred the beers to CO2 purged kegs and placed them in my keezer where they were put on gas to carbonate.

After 2 weeks of cold conditioning, the beers were ready to serve to participants.

| RESULTS |

A total of 24 people of varying levels of experience participated in this xBmt. Each participant was served 1 sample of the direct pitch beer and 2 samples of the rehydrated beer in different colored opaque cups then asked to identify the unique sample. While 13 tasters (p<0.05) would have had to accurately identify the unique sample in order to reach statistical significance, only 11 (p=0.14) did so, indicating participants in this xBmt were not able to reliably distinguish a beer made with dry yeast that was directly pitched on the wort from one where the yeast was rehydrated prior to pitching.

My Impressions: Given the results of Marshall’s experiment, I expected to not notice a difference between the beers, and that’s exactly what happened. Out of 4 blind triangle tests, I only picked the odd-beer-out 2 times, and even then I was guessing. Regardless of my focus, attempts to set aside bias, or even beer temperature, the samples were indistinguishable to me. Interestingly, my wife, who was 38 weeks pregnant at the time, consistently identified the unique sample 3 triangle tests based on aroma alone. I thought the beers tasted great! Not quite as malty as I prefer Munich Dunkel to be, but noticeably bready and toasty with a light chocolate character. The body was also little thin for my tastes, which I might fix by upping the amount of Munich in the grist.

| DISCUSSION |

Yeast manufacturers are under immense pressure to produce a consistent product. As such, they take great care to ensure each batch of beer that follows the manufacturers’ recommendations produces the intended outcome. Without knowing much about Lallemand’s quality control standards, I would assume they’d want to minimize the number of bad outcomes produced by their yeast. If 1 out of 100 direct pitched batches comes out bad, that’s likely something Lallemand would want to avoid. It stands to reason, then, that Lallemand’s instructions for using dry yeast would aim to create ideal circumstances for the yeast to make great beer, which makes the non-significant results from this experiment all the more interesting. Maybe if this experiment were repeated 100 times, we might see a significant result often enough due to damaged yeast cells from direct pitching. But in my opinion, brewers may want to view these instructions as best practices rather than prescriptive ones– and make your own decisions from there.

A scientist described significance to me as an astonishment factor: “So many people guessed the correct result that I would be astonished if this result was the product of random chance.” It is not conclusive proof that a variable does or does not produce a noticeable effect. It’s possible that future exBEERiments on this variable could yield a significant result. It makes sense that manufacturers would recommend rehydrating yeast as a preventative measure, even if the potential for bad outcomes is unlikely.

Many of the brewing texts that recommend rehydration were written quite awhile ago, and a lot has changed over the years. It’s entirely possible ingredient quality and standard brewing practices have improved such that the dry yeast of today is hardier and less likely to suffer from the potential negative effects of direct pitching. Alternatively, maybe the different pitching methods did produce a difference and tasters simply weren’t able detect it to significant degree. Either way, with my results corroborating Marshall’s initial findings, I’m inclined to continue skip the rehydration step and pitch dry yeast direct directly into the wort, even if it means slightly longer lag.

Cade Jobe is a Certified Cicerone and Certified Beer Judge (BJCP) living in Austin, Texas. He is a member of the Austin ZEALOTS who loves brewing and spending time with his wife, future (human) son, and his current children– two dogs named Juno and Jasper. Follow Cade on Instagram, Twitter, and UnTappd.

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

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