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Notes from a travelling Castle Rockian: Lewis' travel diary from our trip to Brauhaus 2.0 in Karlsruhe, Germany.

This July, developmental brewer Dan Gilliland and I flew to Karlsruhe to brew a special collaborative beer with Brauhaus 2.0. The project was in celebration of 50 years of twinship between Karlsruhe and Nottingham. Brauhaus 2.0 is both a brewery and a restaurant located in the Knielingen 2.0 district of Karlsruhe (North West of the city). The “2.0” refers to the development of the area’s economy and infrastructure.

It was a great privilege for us to be invited over to Karlsruhe to brew with Brauhaus 2.0. Yes, it was a way for us to demonstrate the relationship between Karlsruhe and Nottingham, but for us it was about learning and exploring new approaches to brewing too. It has made me realise how important it is to take yourself out of the UK scene for a while (which is transient and, at times, can be clique-driven).

The essence of the collaboration was to be that of sharing and learning. So, we contributed hops and yeast that Brauhaus 2.0 would not normally have access to: S04, and Simcoe/Columbus/Amarillo both whole leaf and T90 pellets. Cramming 8.5kg hops into a hand luggage suitcase was quite a challenge, as Dan can attest…


Wednesday 3rd July


Dan and I left for Stansted Airport on the train – a three-hour slog with an hour wait at Ely (a first for both of us). Overall, not a bad little trip punctuated by coffee, cake and Dan’s overview of his trip to BrewDog the week prior.

The looming niggle was whether we were going to get stopped at airport security for taking a case full of hops. For those who don’t know, hops, or the humulus lupus plant, actually belong to the same family as cannabis. They look (and in some cases smell) very similar.

Now, the anxious little creature I am, I had rung ahead to London Stansted airport, Karlsruhe Baden-Baden airport and Ryanair. All seemed okay ‘if the other was happy with it’ which formed a frustrating endless loop.

So we went for it, and I stood nervously at the conveyor belt where the cases get separated for further investigation. Even though I knew we were doing NOTHING wrong, I doubted things would go smoothly… and Lo and behold, the case got separated.

‘Err… what have you got in here?’ Asked the woman as she opened the case.
‘Hops for making beer,’ I replied, with what I hoped was a polite smile.
The woman disappeared. She talked to a colleague. They looked at the ‘goods’. And then back at me.
‘You’re making beer?’ she repeated.
‘Yeah, we’re going to Karlsruhe to do a collaboration brew with another brewery,’ I said, stomach in my throat.

Then her face softened. She wished me well and told me I could go. Beer really does bring people together. All was well, deep breaths.

Naturally, we were pleased that one of the few hurdles had been accomplished, so we took a celebratory photo.

Surprisingly okay but criminally overpriced airport food and a pint later, and as I write this we’re boarded and all set to go.

Karlsruhe is in South West Germany, and so was almost bang in the middle of Europe’s rather hefty heatwave. Typically, neither me or Dan do well in hot weather, so we’re not looking forward to landing in 30C heat. Still, we we’re really excited to see Jochen and the brewery.


The trip from Baden-Baden to Karlsruhe was an interesting one. The bus (which you need to alight at Rastatt) takes you through suburban Hügelsheim and Iffezheim. Both kinda sleepy areas with an eclectic architectural mix of traditional and ultra-modern.

It wasn’t long before we were rattling into Karlsruhe HBF (Hauptbahnhopf) and looking out for Jochen, who emerged with his colleague, Carol, who looks after operations. They very kindly gave us a lift to Brauhaus 2.0 where we were treated to a delicious meal of pork cheek and spätzle (meaning ‘little sparrows’, a pasta-like dish mostly unique to Southern Germany). Then it was time to talk beer.

Naturally, Dan and Jochen did most of the talking as they worked out the best malts to use, EBC colour ratings, mash efficiencies, hopping process, yeast pitching and timings. With reasonable haste however, we were pretty set for the tomorrow and Jochen took his leave to head to the new Brauhaus site that they were opening.

He’s a relaxed character; you wouldn’t think he was amidst the stress and pressure of opening a new brewery and restaurant! We know what that’s like, and we have never been that relaxed. There’s a lot we can learn!

It’s only 10pm now but a combination of two beers, the heat and a day’s travelling has tired us out. Well, we are both 30-odd now, and Dan is struggling with temporary deafness from the flight.

Thursday 4th July


We were up pretty sharpish (07:00) this morning but that is still a wee bit later than Dan’s used to for a normal Castle Rock brew day. We missed breakfast in the hotel, but headed down the sunny, sedate morning streets of Karlsruhe in the hope that pastries and coffee would come into the mix at some point during the morning.

There was a tentative ‘Hallo?’ when we arrived at Brauhaus 2.0 and met our two wonderful colleagues for the day, brewers Jules and Florian. The brew sheet was ready, the malt grist was ready, and we were ready to go (after a coffee).

We brewed 1000L for this recipe, and the malt grist comprised mostly of pale Vienna malt and a touch of Pilsner malt to bring the colour to a slightly paler golden. Brauhaus is an organic brewery, and they receive their malt uncrushed so, directly before mashing in, the malt gets milled. Quite the novelty for us, having been used to crushed malt.

It’s important at this stage to mention that there are two main mashing in processes, the single infusion mash and the step mash. A single infusion (which is Castle Rock’s process) involves steeping the mash in liquor (hot water) for a period of time and holding at a temperature of about 65C. This provides many chemical functions including encouraging enzymatic activity, controlling pH and converting long-chain starch into short-chain fermentable sugars.  The step mash involves mashing in and leaving the wort (malt and liquor combined) to rest at certain temperatures. One of the justifications for step mashing is that some cereals are less ‘modified’ meaning that step mashing is required in order to trigger the varying chemical reactions that are needed to brew beer. At Brauhaus, the malt underwent an acid rest at 50C, a protein rest at 60C and then a starch conversion at 75C. In its entirety, the mashing in process at Brauhaus took around 2 hours, as opposed to Castle Rock which is around an hour. It was illuminating to see, for both of us, a process like this on a commercial level.

While the mash took place, we hit the local supermarket for much-needed subsistence. It was only a short walk, but temperatures were hitting the late 20s already (scorchio!). Iced tea, juice and colossally large pastries later, and we were ready to check on progress with Jules. Over on the hot side, this time.

While we were brewing, I couldn’t stop thinking what a beautiful kit they have here. Brauhaus 2.0’s set up looks wonderfully simple: a two-tank hot-side set up in copper which comprises a mash tun (which doubles up as a kettle) and a lauter tun. In the middle of the two sits a control panel that makes Jules look like a scientist programming a rocket for launch. Neat!

Next, it was time for lautering, which takes about two hours or so. (This is another process we don’t use at Castle Rock, instead we run the wort off the mash straight into the kettle for the hop additions.) It involves slowly separating the wort from the malt. The entire mash is transferred to the lauter tun and then the wort is recirculated through the malt bed, which extracts extra sugar and also acts as a filter bed. There’s then a short sparging period where hot water is sprayed on top of the mash.


We decided to stop for lunch – the classic schnitzel! The restaurant and bar slowly filled with regulars drinking pints of Pils, Weizen and IPA brewed on site. It was a pleasant, warm and calm atmosphere and amazing to be part of.

We were joined by Simone from the Karlsruhe Council and her colleague and apprentice, as well as Markus from Kambeckfilm, who were due to film a video of the collaboration. We had a great catch up, chatting all things Karlsruhe, its history and what the future holds for it (nice to hear about their green initiatives) and then it was time for hop additions because we were at the boil stage of the process.

We brought both whole leaf and T90 hops with us. Brauhaus don’t normally use whole leaf so we used their perforated steel cage as a container for the hops and immersed that into the wort. A fine piece of engineering! The hop bill is a combination of Columbus and Simcoe for bittering, and then a second charge of Columbus and Amarillo for flavour and a touch of aroma, plus more bitterness. The smell of the hops was intense, and you could tell that we were generating a bit of excitement among the staff who were joining us in the brewery to catch that aroma: a gorgeous bouquet of rich pine, citrus and juicy tropical fruit. Simone’s first impression was ananas which is pineapple. She’s right!

The hopped wort needed to be transferred to the cellar side of the brewery for the yeast addition. Before the yeast could be added however, the beer needed cooling to 19C to create an ideal environment for pitching. I was given the honour of sprinkling the yeast into the hopped wort, but I was surrounded by cameras and lights! It’s amazing how difficult the simplest of tasks becomes when there’s a lens in front of you. I also don’t think my hands had ever been so sterile (and rightfully slow! Yeast can be infected; it’s the driving force of beer and it needs looking after).

When fermentation was complete, it was time to add the dry hops – a combination of Simcoe and Amarillo. This will add a punchy, fruity aroma that gives the beer a distinct freshness of character. It’ll perhaps be something a little different to what the patrons of Brauhaus 2.0 are ordinarily used to. Unlike Castle Rock, Brauhaus 2.0 are leaving the beer over the dry hops for approximately 14 days. This will give it ample time to condition before it gets launched both at the bar and also on the 24th July for the first of the official celebrations of Nottingham and Karlsruhe’s twinning!

After a bit more filming and some video interviews (Hollywood, baby!) with Jochen, Dan and I, we grabbed some showers and headed back to Brauhaus for their Summer Party, which is serendipitously happened while we’re here.

What a night! We sat just to the right of the live music, which was a wonderfully eclectic pop-like performance to a rapturous Thursday night crowd, accompanied by a BBQ, azure skies, beer and the fantastic company of Julian, Jochen, Carol and their colleague Arno. A great, chilled way to cap off an educational and inspiring day.


Friday 5th July

On the plane home now, tired and happy.

We’re really hoping to be able to get hold of some of this beer and bring it back to Nottingham for everyone to try. It was truly a privilege to be there and we couldn’t be more grateful to Jochen, Julian and the Brauhaus 2.0 team for their hospitality and knowledge.

We’re inviting them to our humble brewery in September and we can’t wait to show you what we’re going to cook up together. We’ll be exclusively launching it at the Nottingham Beer and Cider Festival in October. We’ll keep you updated, especially for those who fancy meeting the pair of lovely brewers.



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