Category Archives: Experiment

Experiment

My Experience with Super F, a Vegan Alternative To Isinglass

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At BrauBeviale in Nuremberg last year, a massive fair of the brewing industry, I very naïvely asked about vegan alternatives to isinglass at the Murphy & Son stand (the main reason to go there was to drink cask ale and maybe score a free t-shirt), and was promptly given a sample of Super F, Murphy & Son’s fining product that can be used in cold tanks and casks just like isinglass, happens to be vegan (it’s silica-based), and according to one sales guy I spoke to a few weeks later in Krákow, is even compliant with the German purity law.

Cask ale served at the Murphy & Son stand. Besides Thornbridge The Union, other cask ales like Timothy Taylor's Landlord were also served.
Cask ale served at the Murphy & Son stand. Besides Thornbridge The Union, other cask ales like Timothy Taylor’s Landlord were also served.

It took a bit longer than originally planned to brew a beer where I could try this out. I eventually settled for a simple recipe for a Pale Mild of 8.5°P (1.034) original gravity:

  • 3.3 kg Mild Malt
  • 0.2 kg Simpsons CaraMalt

And simple hop additions which should end up at about 18 IBU:

  • 22g East Kent Golding (5.8% alpha acid) @ 60 min
  • 18g East Kent Golding (5.8% alpha acid) @ 5 min

Mashing was fairly straightforward: single step infusion mash, though I may have slightly overshot the target temperature, as on brew day, I didn’t feel the best and thus didn’t pay as close attention to the brewing process as usual, which later showed in the final gravity of 3.5°P (1.014). I pitched a sachet of Lallemand Windsor Yeast, which was pretty much finished fermenting rather quickly, within 4 days.

After fermentation, I put the beer in my beer fridge to chill it down to about 5°C. Super F comes with a guide how to use it, and most importantly, how to trial the right dosage for your beer. Having only brewed 22 litres, I unfortunately didn’t want to use up quite so much beer to find the right dosage, so I just eyeballed it and picked the middle of the recommended dosage of 75 to 175 ml/hl – 125 ml/hl, i.e. about 25 ml for my homebrew-sized batch. I measured it out, and added it straight to the cold beer.

Me holding the Super F packaging. On it, it says: VEGAN FRIENDLY. SUPER F BEER CLARIFICATION. 100% clearer beer, 5% reduced water & energy intensity. Super F from Murphy & Son is a silica-based liquid fining added to fermented beer in the cold tank, to greatly speed up the sedimentation of yeast and other haze-forming particles. Beer clarity is greatly improved, meaning it can be served fresher and faster. Our recently reformulated Super F fines your beer even faster, leaving your beer clear with a compact sediment. WWW.MURPHYANDSON.CO.UK
Me holding the Super F packaging.

Normally, the Super F should do its trick within just a few days, but life got in the way and we only managed to bottle the beer two weeks later (bottle-conditioned, of course), with another 13 days of refermentation (at the time of writing) in the bottle.

So just earlier, I poured the very first bottle. Just look for yourself:

A Nonik pint glass into which I poured the amber-coloured beer. Since the bottle is 500 ml, it's not quite full. The glass wasn't perfectly clean, so some nucleation points show. You can recognise a reverse "RS" in the back of the glass, which is from the branding of the glass, and gives an indication how clear the beer is.
A Nonik pint glass into which I poured the amber-coloured beer. Since the bottle is 500 ml, it’s not quite full. The glass wasn’t perfectly clean, so some nucleation points show. You can recognise a reverse “RS” in the back of the glass, which is from the branding of the glass, and gives an indication how clear the beer is.
Me holding up the glass after a few sips. It is pretty much clear.
Me holding up the glass after a few sips. It is pretty much clear.

The beer came out pretty much clear. It was a wonderful colour, which against the light makes it appear absolutely brilliant.

It also tastes really nice: with just a hint of hop aroma, it starts very light but then turns out to be quite full-bodied, with a lasting biscuity finish. Since this beer is bottle-conditioned, the carbonation is relatively light and very well integrated. Together with the clarity that is equal to isinglass-fined cask ales, this is probably the closest I’ve gotten to reproducing something like a cask ale at home where everything is right: the flavour (thanks to British malt and hops), the clarity (thanks to Super F), the carbonation. It drinks exactly like a cask ale, too.

All in all, I’m absolutely impressed. Clarity has always been something I’ve struggled a bit with my home-brewed beers (Irish moss only gets you so far), in particular with chill haze. The Super F was very easy to use and did exactly was the product description said. The provided instructions were clear and got me exactly the result that I wanted.

I sincerely hope that Murphy & Son will eventually make this available not just to commercial brewers, but also to home-brewers. The sample I got at the BrauBeviale industry fair will last me for a few more home-brewed sized batches, but I would actually be willing to pay money for the product, provided the price is right.

(Full disclosure: I was given a sample bottle of Super F for free in November 2024, as well as a Murphy & Son t-shirt and a few half-pint pours of cask ale)

Brewing, Experiment, Recipes

My Kellerbier Experiment 2024

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I don’t homebrew that much anymore these days, at most 4 to 5 times a year, and really only the beers that I absolutely want to brew and drink, which includes fixtures like an 8° Czech-style pale lager for summer and a Czech-style dark lager (which I brew with Ben) for winter. So there is really not that much room for experimentation, simply because I don’t have the time, the drinking capacity (I’m 40, it’s all about quality over quantity now) or the resources like free fridge space for fermentation and lagering.

But there have been a few things that I kept wanting to try out, all in the context of Franconian Kellerbier that I had learned about in the last year or so.

The first thing was when my friend Joe Stange visited Brauerei Knoblach just outside of Bamberg end of last year, and came back with the information that Knoblach generally uses a 1:1 blend of Pilsner and Vienna malt as a grist, that their water is fairly hard parts of the year, and that they rely on that hardness (though he couldn’t provide any concrete numbers, nor was I able to find any analytical data about the water of Schammelsdorf, where the brewery is located). I really like Knoblach’s beers, and I know its peculiar taste, so I was wondering whether these were two factors that played into it (Joe also published an excellent article about Kellerbier in the latest issue of Craft Beer & Brewing magazine which does not seem to be online yet, but as a subscriber myself, I highly recommend getting an online subscription).

The second thing was what I learned at HBCon earlier this year about how Mönchsambacher brewed their Weihnachts-Bock. The two things I wanted to incorporate were their mash profile (which I wrote about in July) and the water profile, which has roughly equivalent hardness of calcium and magnesium, and plenty of it as sulphates. Luckily, my local Berlin tap water has about the right calcium hardness, so all I needed to do was to add the right of magnesium to get my tap water roughly where the Mönchsambacher water is in terms of hardness and mineral composition.

The third point on my agenda of things to try out were Aurum hops, a relatively new German hop variety that was launched as more disease- and climate-resistant with a “highly fine” aroma. As a daughter of Tettnanger, it is meant to replace Tettnanger and similar varieties, and German hop growers as well as hop merchants have been promoting it because they see it as a variety better suited to climate change than others, including German landrace varieties. What I wanted to know was well the hops fared in a traditional style.

I know, integrating all three elements in a single experiment is not exactly scientific, as I don’t have a baseline to compare it to, nor do I isolate any of the multiple variables. I’ll still call it an experiment simply because I want to know what a beer brewed that way would taste like.

And that’s how I formulated the recipe:

The grist was simple: 50% Pilsner malt, and 50% Vienna malt. As hops, I used Aurum hops, with additions at 60 minutes for bittering, 25 minutes for flavour, and to the whirlpool for aroma, which should end up at 41 IBU (calculated):

  • 2.3 kg Pilsner malt
  • 2.3 kg Vienna malt
  • 30 g Aurum hops (5.8% alpha acid) @ 60 min
  • 30 g Aurum hops (5.8% alpha acid) @ 25 min
  • 40 g Aurum hops (5.8% alpha acid) @ whirlpool for 20 min

My tap water needed to be enriched with magnesium, so I simply spiked the mash with food-grade epsom salts (MgSO4). According to my calculations, 18g should get me the right amount of magnesium hardness for 22 liters of beer.

As yeast, I used the Fermentis S-23 dry yeast strain. It’s not my absolute favourite, but it’s all I had at hand, also because I had forgotten to order anything else, which is all my bloody fault.

When it came to mashing, I just stuck to the Mönchsambacher mash profile, a single decoction mash. I boiled the wort for 60 minutes, then cooled it down to 6°C, pitched the yeast, and let it ferment at 10°C until it was finished fermenting. I then ramped down the temperature to 1°C for a week, and bottled it with wort I had held back for bottle conditioning.

The resulting beer has an OG of 11.6°P (slightly lower than a typical Kellerbier, but that’s mainly from me buying the ingredients and only afterwards deciding on a mash profile with a slightly lower efficiency than my regular double decoction mash), and fermented down only to 3.5°P FG, resulting in just 4.3% ABV.

A Willibecher of the Kellerbier. The colour is golden with a tiny bit of haze, with a moderately dense head of foam on top.
A Willibecher of the Kellerbier. The colour is golden with a tiny bit of haze, with a moderately dense head of foam on top.

A first taste test showed that the experiment, in my opinion, was successful: the beer has a minerality and a maltiness very much reminiscent of Knoblach and Mönchsambacher. The same goes for the bitterness: while it’s not quite as pronounced as I hoped it would be (I blame the low attenuation which probably leaves just enough residual sweetness to slightly mute it), as it is very lingering: even minutes after, that hop bitterness just stays on your tongue. Which is exactly what I appreciate so much about these beers.

As for the hop aroma of Aurum itself: there’s not that much there. Even though I kept the hops in the fridge and sealed at all times, it was not the freshest batch (2021 harvest), so that may have had an influence. Still, the bitterness the hops provide was quite on point.

Still, I’m very happy with the end result. I think it shows that the local water profile of Bamberg’s surrounding area has a large impact on the flavour of the beer, as long as breweries don’t soften or otherwise treat the water and embrace their very local water profile instead (which is one of the points that Joe makes in his article).

Even the yeast played out alright: I didn’t like S-23 in the past because it can produce rather fruity fermentation byproducts. In this case, the beer came out fairly clean, just with a high final gravity. In retrospect, that actually wasn’t too surprising, as S-23 is the closest known relative of the Wyeast 2001 strain, which is purported to be the Pilsner Urquell “H” strain, and is also known for relatively low attenuation.

My take-aways of this brew are the following:

Hard water, especially similar to the Mönchsambacher water profile, can get you a flavour profile in beer that is similar to the slightly rustic flavour profiles of beers like Mönchsambacher, Knoblach and others in the region.

The combination of Pilsner and Vienna malt probably adds to that rustic character.

A lower attenuation seems to help with the style, but another experiment to try out a more highly attenuating yeast should bring more clarity.

Aurum hops are probably okay for standard German styles, but also require more experimentation to understand their exact aroma potential and how to use them. A more recent harvest would be great to try next time. I generally support the idea of hop varieties that are better suited to climate change (which is an inevitability that will hit the brewing industry hard in the decades to come, so good on German hop breeders to be as forward-thinking as that), as long as we understand well enough how to apply the hops to get the same aromas and flavours as with more traditional varieties.

Experiment

Experiment Time: Does Lactic Acid Skew Refractometer Readings?

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In a Facebook group I follow, an interesting problem came up. Somebody had brewed a mixed-fermentation Berliner Weisse with brewer’s yeast, lactobacillus brevis and brettanonymces claussenii. They didn’t own a saccharometer, but instead determined their OG with a refractometer. They now wanted to know whether fermentation was finished, and used the refractometer as well to measure the beer that had been in the fermenter for several weeks.

Before I continue, a quick excursion into how refractometers work. Every translucent material bends light to a certain extent, the light gets refracted. To describe the extent with which the light is bent, the so-called refractive index is used. The refractive index n is defined as n = c / v, where c is the speed of light in a vacuum, and v is the speed of light in the particular medium. Water for example has a refractive index of 1.333. When we dissolve sugar in water, the refractive index of the solution is increased. The refractive index of a 10% glucose solution in water is 1.347, for example. This change in the refractive index can be used to indirectly measure the OG, by looking at the difference between the expected refraction of water vs the measured one, i.e. by how much more light gets refracted.

In fermented beer, this gets trickier, because due to fermentation, the resulting liquid contains ethanol. Ethanol has a refractive index of 1.361, which skews the overall measurement. Ethanol also skews the measurement when determining the FG of a beer, as its specific gravity is just 0.79. In typical fermented beers, the amount of ethanol is large enough that we need to correct our measurements to be able to estimate the actual FG. This is all fine.

The mixed fermentation opens up another problem, though. It has a refractive index of 1.427 which significantly higher than that of either water or ethanol, but in typical fermented sour beers, its content by weight is fairly low compared to e.g. ethanol. According to this presentation, typical Berliner Weisse contains 2 to 4 g/L of lactic acid, i.e. 0.2 to 0.4% by weight.

When I read about the issue of seemingly underattenuated Berliner Weisse, one of the things that came to my mind was exactly whether the lactic acid from the mixed fermentation skewed the measurement enough to cause such a large disparity that a beer that is expected to be overattenuated to come up with an apparent attenuation of just 68%.

So I asked myself the question: if I added the typical concentration of lactic acid in a Berliner Weisse (i.e. 2 to 4 g/L) to distilled water, by how much would my refractometer be skewed?

I have a refractometer at home, 2 litres of distilled water, a big bottle of 80% lactic acid, and pipets with which I can measure out millilitres of lactic acid. But how many grams is a millilitre of lactic acid? A millilitre of pure lactic acid weighs 1.357 grams, therefore a millilitre of an 80% solution would weigh would weight about 1.285 grams. Since I want to test a whole range of lactic acid content, just measuring out by ml is good enough for me.

I poured 1 litre of distilled water into a clean vessel, and calibrated my refractometer so that it shows exactly 0°Brix. I then added 1 ml of lactic acid (= 1.285 g), stirred it well, and measured again with the refractometer. I measured X°Brix. I then repeated this to up to 5 ml of lactic acid (= 6.425g), and got the following measurements:

  • 1 ml (~ 1.3g): 0°Brix
  • 2 ml (~ 2.6g): 0.2°Brix
  • 3 ml (~ 3.8g): 0.4°Brix
  • 4 ml (~ 5.1g): 0.4°Brix
  • 5 ml (~ 6.4g): 0.6°Brix

This was actually less skew than what I had expected. For a quick counter-check, I added 80% lactic acid on the refractometer, and the measurement was off the scale.

Luckily, I have a Berliner Weisse maturing at home. I brewed it a few months ago, mixed fermentation with S-04, Lacto brevis and Brett bruxellensis. I simply lautered and sparged 30 litres of wort from a 50% Pilsner/50% pale wheat malt mash, which turned out at 11°P OG (unboiled, of course). On my refractometer, I measured 5.2°Brix, while with my saccharometer, I measured 2.0°P. I used calculators to get the expected attenuation based on the OG (in Plato) and FG (in Plato) resp. refractometer reading (in Brix). For both values, I got almost the same level of attenuation (81.82 vs 82.11 apparent attenuation) as well as almost the same ABV (4.7% vs. 4.72%). This is fairly consistent with what I’ve measured earlier, namely that the amount of lactic acid in Berliner Weisse has very little impact to skew a refractometer measurement.

Nevertheless, I think it goes without saying though that a brewer should never ever rely on a refractometer alone. While I use one during my home-brewing, I only ever employ it to measure sugar content ad hoc during the brew day: it’s useful to observe saccharification of your mash, the strength of your first runnings, as well as the sugar content in your final runnings, or to get a good idea about the pre-boil gravity and post-boil gravity of your wort. It’s a tool that has its place, but for observing the progress of fermenting beer, I think it’s a much better idea to just use saccharometers. Even quite precise ones, with a scale down to 1/10 of a degree Plato, and thermometers for further correction of the measurement, are not exactly expensive.