Author: Ray Found

When I first made the decision to go all grain, I discovered there were myriad ways to do so– traditional 3 vessel fly sparge, cheap-and-easy 2.5 vessel batch sparge, and Brew In A Bag (BIAB) were all considered. Most interested in taking the path of least resistance, and considering I had only an 8 gallon kettle for 5 gallon batches, I quickly ruled out BIAB. While the professional look and feel of a 3 vessel fly sparge setup was appealing, it seemed really cumbersome and had the highest startup costs. That left me with the batch sparge method where my boil kettle would perform double-duty as a hot liquor tank and the sweet wort would be collected in my bottling bucket. I had a 48 quart cooler lying around, which after a quick trip to the hardware store for some plumbing parts, became my first mash/lauter tun (MLT).

Despite modifications to accommodate larger batch sizes and brewing 2 batches simultaneously, my current brewing process remains largely identical. Truth is, I’d never considered trying anything different, dismissing other methods early-on undoubtedly due to my own biases. Having acknowledged this, I recently began thinking about the fly sparge method from a slightly more objective perspective. While I never fully bought the claim it necessarily yields higher efficiency than other methods, I wanted to see for myself, and more than that, I was curious if fly sparge might impact a beer’s character in ways batch sparge doesn’t.

| PURPOSE |

To evaluate the impact different mashing methods have on beer, the same recipe was brewed simultaneously using either fly/continuous sparge or batch sparge.

| METHOD |

Having agreed to provide beer for a relative’s wedding, something tasty-yet-approachable for both craft and macro drinkers in the crowd, I thought a light, crisp lager would fit the bill perfectly.

Make It Rain

Recipe Details Batch Size Boil Time IBU SRM Est. OG Est. FG ABV 11 gal 90 min 39.3 IBUs 3.7 SRM 1.060 1.014 6.1 % Actuals 1.06 1.01 6.6 % Fermentables Name Amount % Pilsen (Dingemans) 21 lbs 93.33 Vienna Malt (Gambrinus) 1.5 lbs 6.67 Hops Name Amount Time Use Form Alpha % Hallertau Magnum 30 g 60 min Boil Pellet 12.1 Saaz 65 g 30 min Boil Pellet 3.2 Saaz 80 g 10 min Boil Pellet 3.2 Saaz 80 g 0 min Boil Pellet 3.2 Yeast Name Lab Attenuation Temperature Saflager Lager (W-34/70) DCL/Fermentis 75% 48°F - 59°F Notes 1.056 OG BATCH Sparge



1.060 OG Fly Sparge









When brew day rolled around, I started the batch sparge batch about 30 minutes before the fly sparge batch and was close enough to my target mash temp.

Since I was using my badass ThermoBarrel mash tuns, I put my old MLT to use as a HLT to assist in the fly sparge process, though never one to abandon my roots, I still collected the sweet wort in buckets and poured it into my kettles.

The batch sparge batch received the typical treatment, the second runnings so clear it almost looked like water.

While I waited for the batch sparge wort to reach a boil, I turned my attention to the fly sparge batch. After heating the initial volume of strike water, I mashed in and hit almost exactly the same target temp.

Following an hour long mash, I transferred the ~170˚F/77˚C sparge liquor by pitcher to a bucket, which I then hauled up a ladder to the HLT. For the first time ever, I thought maybe a pump would make life easier. The temperature settled in at 166.6°F, revealing that fly sparging is indeed of the devil.

After a brief vorlauf, I allowed the sweet wort to gently flow from my MLT at a rate similar to that which the sparge water was flowing into the MLT, aiming to keep about an inch of liquid atop the grains. I used a low-tech approach to make sure the sparge liquor didn’t cause any channeling.

Once the sparge was finished, I noted the batch sparge grainbed had a thick pasty substance on it, which was familiar to me, while the fly sparge batch had none. Interesting.

I began the boil and set to the task of weighing out hops… I guess I’ll need to order more soon.

At the conclusion of their respective boils, each beer was chilled rapidly to just above my warm groundwater temp then placed in a regulated chamber where they would sit until dropping to my target 56°F/13°C fermentation temperature. A check of the original gravities revealed my original presumption was wrong, the fly sparge wort was .004 SG higher than the batch sparge wort, resulting in brewhouse efficiencies of 78.8% and 73.5%, respectively.

The next morning, wort temps had stabilized and I pitched a pack of rehydrated 34/70 into each fermentor. The beers were fermenting healthily a couple days later.

With active fermentation appearing complete, I took a hydrometer measurement that revealed both batches had reached an identical FG. Huh.

Two weeks after brew day, the beers were cold crashed, fined with gelatin, kegged, then placed in my keezer to condition and carbonate. After a mere 24 hours, I pulled a couple samples and found them not only delicious, but amazingly clear for a beer brewed just 20 days earlier!

| RESULTS |

Thanks to all of the family, friends, local homebrewers, and club members who participated in this xBmt, there were 16 in all. Each blind participant was served 1 sample of the batch sparge beer and 2 samples of the fly sparge beer in different colored opaque cups then asked to identify the different one. Given this sample size, a minimum of 9 (p<0.05) would be required to correctly identify the odd-beer-out in order to, which is exactly how many did (p=0.026). These results suggests a pale lager made using the fly sparge process is reliably distinguishable from the same beer made using the batch sparge process, at least to this particular panel of tasters.

Responses regarding preference and ability to correctly identify the batch sparge beer yielded nothing of meaning, as responses were split pretty evenly on each question.

In conversations following completion of the survey, several panelists who were correct on the triangle test used adjectives such as crisper, drier, and hoppier to describe the batch sparge beer, which to me seems congruent with the fact it starting at a lower OG. But who knows?

My Impressions: Chock one up for the panel! In 3 “blind” triangle test attempts, I managed a correct response only 2 times. Armed with my bias, knowledge of the variable, and hubris, I believe I was able to identify some of what the panelists were saying, particularly that the fly sparge beer seemed a bit maltier, richer, and fuller, if only ever so slightly, and like the panelists, I had no preference for one over the other.

If served back to back, there is absolutely no way I’d be able to identify the beer had changed, I freely went back and forth between the two taps. I ended up taking a full keg of the batch sparge beer to the wedding where I’m pleased to say it was enjoyed thoroughly by the bride, groom, and their guests.

| DISCUSSION |

Given what I believe to be a fairly surprising difference in gravity, I guess I shouldn’t be shocked the panel was reliably able to discern a difference. With over 0.5% difference in ABV, it isn’t really a shock that the beers were perceived as being different, but still, this wasn’t the result I expected.

Personally, I’m inclined to view the difference in OG as the result, not only because it objectively seems to confirm the conventional wisdom that fly sparge can yield better efficiency, all else being equal, but it seems at least probable it’s what the panelists were reacting to. Maybe this is an overly simplistic perspective, or perhaps just my desire to maintain the position that identical beers can be produced using either method.

Ultimately, while I’ve no plans to abandon the method I’ve come to trust and know so well, this xBmt was a bit of an eye-opener for me and I look forward to learning more about the impact other mash methods have on beer.

What’s your mash method of choice? Are you a die hard fly sparger, a cheap and easy batch sparger, or do you BIAB? Perhaps you started with one method and switched to another? Whatever it is, please share your experiences in the comments section below!

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