June 2023

This year, we started experimenting with new hop products on our way to achieving the lowest possible alcohol content in pale ale beers.
The hops used on March 8, 2023 The beers brewed on March 2023, in which a new hop product was used for dry hopping in 5 variations, showed alcohol contents of between 3 and 4 % vol. at an original gravity of around 11.5 °P with an aroma profile typical of the respective hops. In the sensory evaluation, the significantly lower alcohol content was not noticed in comparison to commercial Pale Ale beers, and the beers were by no means lacking in aroma.
However, two of these hop variations showed a noticeable hop creep, which was very clearly expressed in the chromatograms of the sugar distribution in a decrease in the higher sugars and measured alcohol contents by 4 % vol, while three of the hop variations caused only a slight reduction in higher sugars. Compared to the base beer, the alcohol content was only 0.2 - 0.5 % vol higher in these three cases.
Our interim conclusion is therefore that with new hop products and isothermal high-temperature mashing, alcohol-reduced but still fruity-flavoured pale ale beers with alcohol contents between approx. 3 and 4 % vol can be achieved.
The beer brewed on February 22nd brewed on 22 February, which was fermented with Mangrove Jack's maltotriose-negative yeast "Empire Ale", showed a surprisingly low alcohol content of only 2.5 % vol, contrary to the expected 3.5 % vol. This pleasing deviation from the expected value has procedural reasons.
 

Based on these results, we brewed on June 24 & 25 and experimented with other new hop products.

Non-isomerized hop extracts produced with supercritical carbon dioxide for Pilsen-style brewing are well known, and we have good experience with them. There are now fruit-flavored hop extracts for the production of pale ale beers that are suitable for whirlpool hopping and also for dry hopping. One of these is the product "Spectrum" from Barth Haas, with which we produce our NEIPA's (New England IPA), which are always very well received. This hop product shows no hop creep and thus allows NEIPA's with approx. 3% alcohol by volume when maltotriose-positive top-fermenting yeasts are used for fermentation.
On one of the brewing days, we produced 200 liters of Pale Ale, 80% of which consisted of Pale Ale malt and 10% each of Carahell and Carapils. We used our BrewTools 150 Pro in two brewing processes, which delivers more reproducible results with 100 liters of water and 20 - 25 kg of malt in isothermal high-temperature mashing than when using the full capacity. Homogeneous temperature distribution during mashing is very important in this mashing process, and this is not always guaranteed when using the full capacity of 150 liters, as automatic mashing cannot take place in the malt pipe technology and mixing must therefore be carried out manually or with a honey whisk. As a result, the beta-amylase can also break down starch for a few minutes and form maltose, which leads to higher alcohol contents.
After 30 minutes of mashing at 74 °C, lautering was carried out, whereby this time - out of experimental curiosity - we washed out the malt with two 85 °C hot second fermentations of 10 liters each. As we kept the temperature of the system at a constant 74 °C during lautering, any starch washed out was saccharified by the alpha-amylase in the wort. Lautering was completed after around 30 minutes, and the wort was boiled for 60 minutes with non-isomerized bitter hop extract.
Less than three hours passed between mashing in and the end of pitching, and the second brewing process started after a brief cleaning of the system a few minutes later with mashing water that had previously been heated externally. This meant that we lost very little time and both brewing processes were completed after around 6 hours. For the whirlpool hopping, we used a new hop extract that is supposed to be completely free of enzymes. This is available in several aroma variants, and we opted for the "Citra" variant.
The wort was then cooled via a plate heat exchanger and transferred to an unpressurized 200-litre fermentation vessel. Cold hopping was carried out with Barth Haas Spectrum in the Citra variant. The 200 liters of wort were fermented with Mangrove Jack's maltotriose-negative "Empire Ale" yeast at around 22 °C, and we are looking forward to the alcohol content and aroma of the finished beer with an original gravity of 11.3 °P.

On the second brewing day, we produced 100 liters of Pale Ale and also used the BrewTools 150 Pro. The malt bill is similar to the one mentioned above, but we replaced Carahell with Carapils and increased the amount of malt slightly. Mashing was carried out as described above, and all other steps including bittering were identical.
Whirlpool hopping was carried out with the above-mentioned hop extract in the "Citra" variant, but for dry hopping we used a new hop extract specially developed for this purpose in the "Citra" and "Simcoe" variants, both of which are typical for pale ale beers.
This brew, which reached an original gravity of around 12 °P, was fermented with Magrove Jack's M66 (Hop Head). This is a commercially available top-fermenting yeast that is enriched with beta-glucosidase. This results in a biotransformation of glycosidically bound aroma substances, which is intended to emphasize the fruity aroma of the beer by releasing the aroma substances.
We assume that beer fermented with M66 will be ready in approx. 4 weeks, as this yeast sediments very well, resulting in a clear beer quite quickly. In comparison, the M15 sediments noticeably worse, so it should take 6 - 8 weeks until the beer has clarified satisfactorily.

On June 19, we once again compared the three brewing processes "High-Short", "High-Short-Ultra" and the isothermal high-temperature mashing process in order to further validate the data obtained in earlier trials. For this purpose, we set up a 3-device brewhouse on a 50-liter scale, consisting of a mash tun with agitator, a post-pour heater, a heated lauter tun and a brew kettle.
This allowed us to produce three brews in succession and mash the second while the first brew was boiling. We needed 9 hours net for the three brews, i.e. without preparation and post-processing, and the so-called bottleneck was the heating time in the electrically heated brewing kettle. If only around 3 kW of electrical power is available to heat around 55 liters of wort to boiling point, then this simply takes time.
We brewed with Pale Ale malt, and in all three trials, exactly 10 kg of malt grist was used for 50 liters of main malt. The second brew of 12 liters each was added in two portions. In all three brewing trials, we took samples for later analysis (free amino nitrogen, sugar) at defined and identical times during mashing and determined the in situ original wort on site. At the end of mashing, which took the same amount of time in all three cases, we obtained virtually identical original gravities of 12 °P in all three cases and identical volumes of 54 liters in the brewing kettle. After boiling for 60 minutes with the addition of sour beer, we obtained 50 liters of wort in all three trials.
Bitter hopping was carried out with non-isomerized hop extract, while we used hop pellets in the whirlpool for aroma hopping (Aramis, Spalter Select). Each of the three wort types is fermented in a cylindrically-conical fermentation vessel at 12 °C without pressure using LalBrew Diamond, a bottom-fermenting Pilsner yeast similar to Weihenstephan W34/70 or TUM W34/70.
These comparative trials confirmed that a mashing time of 30 minutes is more than sufficient for isothermal high-temperature mashing, with the remaining saccharification taking place during lautering. In this way, mashing and lautering are completed after 60 minutes, and if the heating capacity of the brewing kettle is sufficient, just 21/2 hours pass from the start of mashing to the end of lautering. We expect the beer brewed using the isothermal high-temperature mashing process to have an alcohol content of around 3% vol. and the other two beers around 5% vol.

On June 17, we produced 200 liters of bottom-fermented dark beer as part of an internal event. The malt bill consisted of 70% Munich malt, 20% Carahell and 10% Caramünch.
The latter deepens the color and brings in intense malty aromas.
Mashing took place isothermally for 30 minutes at 74 °C in the BrewTools 150 Pro, but we only used 2/3 of its capacity and therefore repeated the brewing process after the first brew. The lautering at 74 °C was completed after around 30 minutes, and after a heating phase of around 20 minutes, the wort was boiled for 60 minutes with the addition of sour wort.
We are currently experimenting quite a lot with hop extract, and so non-isomerized hop extract made from Hallertau Tradition was used for both the bitterness and the aroma. As written in previous brew reports, the use of hop extract does have some advantages. We have been able to reproducibly observe that the brewing system is much easier to clean after hop boiling, there is noticeably less deposits on the heating coils and there is no risk of the plate heat exchanger, which is used to cool the wort after boiling, becoming clogged.
With hop pellets, the plate heat exchanger can gradually become clogged, as no trub cone is so perfect that no particles are removed from it. Removing hop residue from welded or soldered plate heat exchangers can be quite difficult, and unfortunately our system does not have a filter for trub particles because the pump is not designed for this. Future sensory evaluations (aka "tasting") will have to show to what extent we can achieve a satisfactory result with hop extract for the more classic beer styles, which is roughly equivalent to that with classic hop pellets.
The wort, which reached an original gravity of around 12 °P, is fermented in our Siegfried tank with White Labs WLP-800, a Czech Pilsener yeast that is intended to emphasize the malt and hop character. Like many bottom-fermenting yeasts, it tends to form diacetyl, which can produce a buttery taste depending on the concentration. Tastes differ in this respect: In the Czech Republic, a subtle buttery diacetyl flavor is definitely appreciated, such as in "Pilsener Urquell", while in Germany it is considered a "no go".
We needed less than 7 hours in total for both brewing processes. Mashing and lautering were completed after 60 minutes each, heating and boiling took a good 80 minutes, the whirlpool took 15 minutes and the lautering itself, i.e. transferring the cooled wort to the fermentation tank, took a good 20 minutes each. We lost time due to the need to clean the system after the first hop boil and to heat up the mashing water for the second brewing process.
The dark beer should mature in 6 - 8 weeks, after which we will brew the dark Christmas bock in Tank Siegfried according to current plans.