Author: Ray Found

When I started brewing, I learned one does not drain the wort from the grains without performing a vorlauf, that is, recirculating sweet wort until it runs clear. It was deemed a requirement that contributes to the full extraction of sugar from the grains, help set the grainbed for effective lautering, and prevent astringency producing grain husks from making their way into the boil kettle. I initially learned about the horror of husks while reading comments about the now infamous Good Eats episode where Alton Brown boiled his steeping grains with extract and hops. Tannins!

It makes sense to me that grain husks might impart some flavor that is different than the endosperm it encases, after all, whole grain bread does taste different than white bread. However, the results from our first vorlauf xBmt showed that tasters could not reliably distinguish between a beer that had undergone a vorlauf from one that hadn’t, making me wonder if perhaps the amount of grain making it to the boil played a role.

We tend to focus our xBmts on the practical, but occasionally a time comes where testing extremes could potentially yield more meaningful information. That time is now.

| PURPOSE |

To evaluate the differences between a beer brewed with a standard vorlauf where very little grain material made it to the boil and another of the same recipe where an extreme amount of spent grain was added to the boil.

| METHOD |

Due in no small part to my difficulty finding Negra Modelo on tap, a beer I’ve no shame admitting I thoroughly enjoy, I put together a recipe for a Vienna Lager, it would be my first attempt at brewing this style.

Vienna Lager

Recipe Details Batch Size Boil Time IBU SRM Est. OG Est. FG ABV 11 gal 90 min 21.7 IBUs 10.3 SRM 1.049 1.009 5.2 % Actuals 1.046 1.011 4.6 % Fermentables Name Amount % Vienna Malt (Gambrinus) 12.15 lbs 60 Pilsner (2 row) (Gambrinus) 5.062 lbs 25 Munich Light 10L (Gambrinus) 2.632 lbs 13 Pale Chocolate Malt 6.48 oz 2 Hops Name Amount Time Use Form Alpha % Hallertau Magnum 23 g 60 min Boil Pellet 12.1 Hallertauer 56 g 10 min Boil Pellet 3.2 Yeast Name Lab Attenuation Temperature German Ale/Kolsch (WLP029) White Labs 75% 65°F - 69°F

For this variable, we determined splitting the wort post mash would increase consistency between the batches, so I performed a standard batch sparge. My brew day began with the heating of strike water, during which I set to the task of weighing out and milling my grain. I’d recently received a new mill and, in my excitement to use it, fashioned up a sheet metal version of my own hopper since the real one hadn’t arrived yet… pretty is not the right word.

The mill outperformed its shitty looks and chewed through 20 lbs of grain in under 2 minutes. I transferred the over-heated strike water to my mash tun, allowing it to preheat for a couple minutes.

Once the liquor had dropped to my target strike temp, I mashed in and came just shy of my intended mash temperature.

I pulled a sample of sweet wort from the mash after about 10 minutes and found it sitting right at what what was estimated by the Bru’n Water spreadsheet.

I’ve always wondered just how much grain is really being filtered out during a vorlauf, so my friend Dave, owner/brewer of Stone Church Brewing in Corona, CA, and I measured it by running the vorlauf wort through a strainer rather than directly back on top of the grainbed.

After recirculating approximately 1.5 gallons of sweet wort, I weighed the detritus– roughly 23 grams/0.8 ounces of grain material. Since I was batch sparging, which involves adding another volume of sparge water and stirring, it can be assumed this proportion would effectively be matched by the vorlauf prior to collecting the second runnings, equaling upwards of 50 grams/1.8 ounces from an 11 gallon batch that would have otherwise made it to the kettle. Albeit, the grains were wet, but still, that seems like a lot. After collecting the entire volume of wort from the mash, I stirred it well then split it into two 6.75 gallon portions, both grain-free. At this point, I decided to simulate a worst-case-scenario and added nearly 200 grams/7 ounces of spent grain directly to one of the boil kettles. No one could vorlauf this badly.

I noticed a difference between the two batches immediately after a boil was reached, with the extreme batch developing a big scab of shit floating on top. Frankly, it looked gross.

Once the boils were complete, I quickly chilled the wort and transferred each batch to matching 6 gallon PET carboys, placing them in my fermentation chamber to finish chilling. Hydrometer measurements at this point revealed the beers were at the same 1.046 SG. A few hours later, the worts had stabilized at my target fermentation temperature of 58°F/14°C, so I split the starter of yeast between the batches. They were chugging along nicely when I checked on them 36 hours later.

After a week, I began ramping the temperature in the chamber to 72°F/22°C where they remained for another week. With no signs of activity, I took hydrometer measurements and discovered both had finished at 1.011 SG.

I proceeded to cold crash, fine with gelatin, and kegged both batches. After about two weeks in my keezer on gas, the beers were clear, carbonated, and ready for evaluation.

| RESULTS |

The bulk of the data for this xBmt was collected at Wagon Wheel Tavern during a BeerMe Brew Club meeting and included 23 participants in total. While 12 tasters (p<0.05) would have had to correctly identify the odd sample out to achieve statistical significance, only 11 (p=0.107) chose the correct sample, suggesting this panel was not able to reliably distinguish between a beer produced using a standard vorlauf and one that had a shit ton of spent grain added to the boil. And though it may not matter, preference among those who were correct on the triangle test was split.

My Impressions: Yuck! When the beer was freshly kegged, before I began serving them to others, I absolutely hated the boiled-grain batch. It tasted strange and had a “twang” to it that reminded me a bit of liquid malt extract, not at all clean or crisp. It just wasn’t good. When I returned to it over a week later, I could still consistently tell the beers apart in multiple “blind” triangles, perhaps biased by my earlier experience. However, the distinct character I initially got from the boiled grain batch was gone and I had no clear preference by the time I administered survey. Moreover, I didn’t experience any of the astringent tannin character I expected, which genuinely shocked me.

| DISCUSSION |

For a second time, an xBmt has supported the idea that the vorlauf step may not be as vital as many of us have have come to believe, even when taken to a drastic extreme not likely to occur in the typical homebrewery, with one exception…

The decoction method involves taking large portions of the mash and boiling it upwards of three times before returning it to the mash. While I’ve read numerous arguments for and against the merits of decoction, one thing I’ve yet to encounter are reports of people perceiving decocted beers as astringent. It’s curious to me that many of the same people who boil heaps of grain later invest such effort in making sure all of that grain remains in the mash tun.

I also wonder about the possibility of a combined variable effect, in this case the time the beer spent lagering. While initially the two beers tasted quite different to me, with the boiled grain batch having a twang that could maybe have been related to tannins, it seemed to diminish substantially over time. It makes sense to me that astringency causing particulate would precipitate during the lagering phase.

In the end, I won’t be dropping the vorlauf step from my brewing routine, if only because I perceived the beer made using my normal process as being better when fresh and I’m slightly impatient. That being said, even with such a large proportion of grain added to the boil, the difference was minor enough to lend credence to the idea that a vorlauf isn’t a vital procedure to make good beer.

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

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