Author: Jake Huolihan

Generally accepted as a flavor neutral compound, phosphoric acid is comprised of 3 hydrogren ions, 1 phosphorus ion, and 4 oxygen ions, and is used in brewing primarily for mash pH reduction. It comes in various strengths, though the most commonly available to homebrewers is 10%. While it works great for its intended purpose, the fact it’s an additive other than water, malt, yeast, or hops means it’s unusable by those wishing to stick to the Reinheitsgebot.

Given the importance placed on mash pH, inventive maltsters developed a product that would allow a brewer to make the necessary adjustment while abiding by the classic German Purity Law. Acidulated malt, also known as sauermalz or just acid malt, undergoes a process that produces naturally occurring lactic acid on the malt, which remains until use. A brewer simply includes a charge of acidulated malt to their grist, usually 1% to 10%, and the lactic acid present on the grain acts to reduce the pH.

Whereas phosphoric acid wins points for being a reliable way to adjust mash pH without contributing any perceptible flavor to beer, acidulated malt is believed by many to impart a unique characteristic that’s actually desirable, especially in German lager styles. I’ve used acidulated malt quite a bit in my brewing and recently made a beer where it made up 10% of the grist, the upper end of most maltster recommendations. I was slightly concerned that relatively high amount might lead to a noticeable lactic character, but it didn’t, the beer tasted largely as I expected. This experience inspired me to design an xBmt to help me understand just what, if any, differences exist between beers made using either phosphoric acid or acidulated malt.

| PURPOSE |

To examine the differences between beers made using either phosphoric acid or acidulated malt for mash pH adjustment.

| METHODS |

I thought a Munich Helles seemed an ideal style to test this variable and designed a simple recipe that would allow any differences to come through.

Tripping

Recipe Details Batch Size Boil Time IBU SRM Est. OG Est. FG ABV 5.5 gal 60 min 22.5 IBUs 3.7 SRM 1.046 1.011 4.6 % Actuals 1.046 1.011 4.6 % Fermentables Name Amount % Pilsner (Weyermann) 8.562 lbs 83.03 Vienna Malt (Weyermann) 1 lbs 9.7 Acidulated (Weyermann) 7 oz 4.24 Carahell (Weyermann) 5 oz 3.03 Hops Name Amount Time Use Form Alpha % Loral 9 g 60 min Boil Pellet 10.3 Loral 11 g 30 min Boil Pellet 10.3 Yeast Name Lab Attenuation Temperature Harvest (L17) Imperial Yeast 72% 50°F - 60°F Notes Water Profile: Ca 62 | Mg 0 | Na 8 | CO4 60 | Cl 68 Download Download this recipe's BeerXML file

I prepared a single large starter of Imperial Yeast A17 Harvest a few days ahead of time. The night before brewing, I collected my water for both batches and adjusted each to the same mineral profile, adding 19 mL of 10% phosphoric acid to only one batch. I then weighed out and milled the grains, replacing the acidulated malt in the batch that received phosphoric acid with an equal amount of Pilsner malt.

I woke up the next morning and turned on the element to heat the water for the phosphoric acid batch. Since this variable required 2 separate batches, I staggered the start of each by 20 minutes and treated them identically otherwise. I transferred the slightly overheated strike water to mash tuns and, after a period of preheating, added the grains and gently stirred to hit the same mash temperature.

Curiously, though obviously a fickle sense, the mash with the acidulated malt seemed to have a slightly tart scent. Both mashes were left to rest.

At 15 minutes into each mash, I pulled samples to check the pH and was satisfied with how close they were to each other.

After each 60 minute mash was complete, I collected identical volumes of sweet wort in separate kettles and proceeded with the boil step.

Following a 60 minute boil, the worts were quickly chilled.

Refractometer readings revealed both worts settled in at nearly the same OG.

Equal volumes of wort were racked to separate Brew Buckets, at which point I decanted the large yeast starter I’d made a few days earlier and split it evenly between the batches.

After hitting each wort with 90 seconds of pure oxygen, I placed them next to each other in my fermentation chamber controlled to 50°F/10°C.

Fermentation was kicking less than 12 hours later and proceeded similar in both beers. With signs of fermentation absent 5 days later, I took initial hydrometer measurements that matched samples taken 3 days later, indicating FG had been reached.

I went ahead and kegged the beers at this point.

The filled kegs were placed in my keezer and allowed to lager for a month while being force carbonated. When the time came to collect data, both beers were carbonated and crystal clear.

| RESULTS |

A total of 23 people of varying levels of experience participated in this xBmt. Each participant was served 2 samples of the beer made with phosphoric acid and 1 sample of the beer made with acidulated malt in different colored opaque cups then asked to identify the unique sample. At this sample size, 12 tasters (p<0.05) would have had to identify the unique sample in order to reach statistical significance, though a total of 15 (p=0.002) made the accurate selection. These results indicate participants were able to reliably distinguish a beer made with water that was adjusted with phosphoric acid from one whose pH was adjusted with acidulated malt.

The 15 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 8 tasters reported preferring the phosphoric acid beer while only 3 said they liked the acidulated malt more. Another 3 tasters reported having no preference despite noticing a difference and 1 person said they perceived no difference between the beers.

My Impressions: I admittedly went into this xBmt fully expecting the beers to be the same, thus confirming my bias that the ease of using acidulated malt was not only ingeniously simple, but it didn’t add or take anything away from my beers. Over a series of 5 semi-blind triangle tests, I was able to identify the unique sample 4 times. It wasn’t insanely obvious to my senses, but there was a noticeable difference, namely my perception of a slightly tart sensation on the back of my throat in the acidulated malt beer. Going even more against my expectations, I chose the phosphoric acid beer as the one I most preferred in all 4 of my correct triangle test attempts.

| DISCUSSION |

Brewers rely on various acids to adjust their mash pH and seem to view most typical options as being largely interchangeable. The two most commonly used acids in brewing are phosphoric acid and lactic acid, the latter of which is organically produced on grain to produce acidulated malt.

It wasn’t until I ran across comments by brewers of traditional German lagers that I even considered the use of acidulated malt might actually have a unique impact on beer character. Having been developed in response to the Reinheitsgebot, to my mind, acidulated malt was simply Pilsner malt with some lactic acid on the outside, which similar to phosphoric acid, is generally accepted to be flavor neutral. For these reasons, I was not expecting tasters to be able to distinguish beers where the mash pH with adjusted with either phosophoric acid or acidulated malt, but rather figured the results would align with those of a previous xBmt comparing phosphoric acid to lactic acid.

We don’t solicit pointed data in terms of the stylistic representation of either sample, so there’s no way to conclude if in fact acidulated malt contributed some uniquely German characteristic to the beer. If it did, it would seem the majority of participants who were correct on the triangle test preferred the phosphoric acid beer more. Of course, preference is subjective, and to me, both tasted good and represented the style well.

While the differences I perceived between the beers in this xBmt weren’t stark, I’ll be relying more on liquid acids mostly because they’re easy to use, though I also had a slight preference for the phosphoric acid beer. However, I certainly didn’t dislike the acidulated malt beer and would use it without question in a situation where a liquid acid wasn’t available. Overall, this xBmt made me all the more interested in exploring the use of ingredients developed out of restrictive beer laws and how their influence shaped the way we perceive certain styles of beer.

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

Support Brülosophy In Style!

All designs are available in various colors and sizes on Amazon!

Follow Brülosophy on:

If you enjoy this stuff and feel compelled to support Brulosophy.com, please check out the Support page for details on how you can very easily do so. Thanks!

Advertisements

Share this: Facebook

Twitter

Pinterest

Tumblr

Email



Like this: Like Loading...