September 2023

Using the isothermal high-temperature mashing process, we can significantly reduce the proportion of fermentable sugars and achieve an alcohol content of around 3 % vol. with Pale Ale malt at original wort temperatures of 12 °P and classic maltotriose-positive yeasts. In the production of Pale Ale beers, the so-called hop creep effect occurs to a greater or lesser extent depending on the hop variety when dry hopping with commercially available P90 or P45 pellets. Enzymes from the hops break down non-fermentable higher sugars into fermentable sugars, so it can easily happen that a Pale Ale with 12 °P reaches an alcohol content of 6 - 7 % vol. due to the resulting overfermentation.
Simcoe and Cascade show a very strong hop creep, while Citra and Ekuanot cause comparatively little overfermentation. Either the hop pellets must be thermally treated before being added to water or wort for fermentation so that the enzymes are denatured without affecting the aroma, or special aroma hop extracts are used for dry hopping, which have no enzymatic activity whatsoever. There are now also aromatic hop extracts that are suitable for whirlpool hopping.
As our low-alcohol Pale Ale beers with around 3 % alcohol by volume are very popular and we can hardly keep up with brewing, we have purchased a second 250-liter cylindrically-conical fermentation vessel, which will be reserved for Pale Ale beers in future. And so on 27 & 28.09.2023 we brewed a total of 200 liters of NEIPA for this ZKG called "Tank Volker".
NEIPA or Hazy Pale Ale are very fruity aromatic and very little bitter Pale Ale beers, almost reminiscent of a fruit juice. Our batch consisted of 75% Pale Ale malt and 25% Carahell. We mashed in the Brew Tools 150 Pro once for 60 minutes, once for 30 minutes at 74 °C, and on both brewing days we obtained almost identical original wort temperatures of around 11 °P.
The wort was boiled together with sour beer and a non-isomerized bitter hop extract, and we added a special hop extract from the company Yakimachief in the "Citra" variant to the whirlpool. The dry hopping in the ZKG is carried out with the hop extract Spectrum from BarthHaas in the "Citra" variant. Both brews are fermented together in Tank Volker with Ebbegarden Kveik, which in turn produces aromas of tropical fruits (mango and guava). This yeast has a beta-glucosidase, which releases glycosidically bound aromatic substances from the hops and thus emphasizes the fruity aroma. Almost all Kveik (yeasts) ferment very quickly, so fermentation at 20 °C will be completed within a few days. The beer should be mature by the end of October and the alcohol content should be a maximum of 3 % vol. In future, we will brew such pale ale beers every 4 - 6 weeks and vary the flavors.

On September 7, 2023, we carried out the last series of tests to compare mashing processes, i.e. we compared the isothermal high-temperature mashing process with the high-short mashing process used in large breweries and a simplified high-short mashing process. The results obtained during mashing were in very good agreement with the two earlier test series, meaning that a very high level of reproducibility was achieved overall. This series of tests has therefore been completed. After evaluation of the data and a sensory assessment of the nine beers at the Center for Brewing and Food Quality (BLQ) at the Technical University of Munich, the results will be prepared for publication.
We also produced a Pale Ale / NEIPA on this brewing day. For this, pale ale malt was mashed isothermally at 72 °C for 60 minutes in our 50 L mash kettle with agitator, and we obtained 50 liters of wort with 12.5 °P from 10 kg of malt. Without going into details at this point, we have observed several times that at the end of the brewing process, regardless of the mashing process, the original wort obtained can vary by +- 0.5 °P from trial to trial, even if there are hardly any significant differences in different trials during mashing, i.e. in situ. This is probably due to the lautering process as well as the sparging applied, because in contrast to large breweries, where there are sophisticated choppers for the lauter tun with optimized application of the sparging, we are dependent on manual loosening of the spent grains cake, which can lead to deviations.
However, even in large breweries, not every brewing process is identical to the previous one, and even there deviations can occur from brew to brew, which can be explained within the framework of random errors. The wort was hopped with a bittering hop extract and the aroma hop Aramis (Pellets 90), and for the dry hopping we added 60 g of the hop extract "Spectrum" from Barth-Haas in the Citra variant. The wort is fermented with the LalBrew "Verdant IPA" so that the overall result should be a fruity, aromatic pale ale / NEIPA with an alcohol content of around 3 % vol.
 

On September 8, 2023, we brewed a desired beer for an upcoming event at Clausthal Technical University. The boundary conditions were: Light, mild and not too bitter, reduced in alcohol with approx. 3% alcohol by volume. As we now receive a lot of feedback on our beers, we can assess quite well in which direction a beer with these characteristics should go. We therefore produced a total of 2x 110 liters of wort each with the Brewtools 150 Pro.
The wort consisted of 30% Pilsner malt, 40% Pale Ale malt, 7% Munich malt, 7% Carahell and 16% Carapils. Mashing was carried out at 78 °C and mashing lasted 30 minutes at 74 °C, followed by 30 minutes of lautering at 74 °C with 80 °C sparge water. The wort was boiled with a small amount of bitter hop extract and Hallertau Mittelfrüh (pellets 90) for 60 minutes. Hallertauer Mittelfrüh was added again 30 minutes before the end of the boil, and whirlpool hopping at around 90 °C was carried out with Hüll Melon Wethop.
We purchased a fine-mesh trub filter for our brewing system, which is integrated upstream of the plate heat exchanger. No trub cone is so stable that trub is not transferred to the fermentation vessel towards the end of the pitching process. Although trub is not a fundamental problem for fermentation and the subsequent taste, hop bitterness and, in the case of dry hopping, aroma substances are also precipitated, reducing the bitterness and aroma yield. In addition, without such a filter, trub and hop particles are introduced into the plate heat exchangers and these can only be cleaned again with great effort. The first tests have shown that the filter reliably retains the trub and hop particles as expected, and that the knock-out into the fermentation vessel is not impaired over a wide range. Only towards the end of the pitching process is the flow rate reduced due to the build-up of back pressure, so that the pitching process takes a little longer than without a trub filter. Including the cleaning work, each brew took around 4 hours.
In the end, we achieved 220 liters at 12.1 °P. The finished beer, which is fermented at 12 °C with the bottom-fermented White Labs WLP-800 in our "Tank Siegfried" without pressure, should contain classic hop aromas, but should also be subtly fruity thanks to the use of Hüll Melon. We expect an alcohol content of around 3 % vol. and a bitterness of approx. 25 IBU. Pilsner malt could also result in a subtle cereal-like taste, which is not unusual for pale ales. We will close the bunging valve approx. 5 days after the start of fermentation so that pressure builds up in a controlled manner during secondary fermentation. After a total of approx. 14 days in the fermentation tank, we will drain off the trub that has collected in the cone and fill the beer into pressure kegs a day later. Further clarification and maturation then takes place at 2 °C in the pressure keg, and the beer should be ready in time for the event at the end of October.