A visit to Guinness brewery

Back in Dublin for the first time since 1911 I finally got to go round the Guinness brewery at St James's Gate. 

Diageo own have Guinness brewed in "46-50" breweries, of which only five brew draught Guinness, most making the far superior Foreign Extra Stout (FES). It has a lot of diacetyl though  (>250ppb!), which just shows that it's not always a bad thing. 

They were in the process of commissioning two new 1000 keg per hour kegging lines when we visited. The fill 20, 30 and 50L kegs, with high gravity beer being cut to sales strength just before packaging. The beer gets 25 Pasteurisation Units (PUs). CO2 is 1.8-2.4 volumes and nitrogen 2.5-4. Which sounds quite a wide range to me but  you can't argue with hastily scribbled notes when you try and decipher them. 

After its initial hiccup Guinness Zero has been way more successful than anticipated. They are however extremely cagey about how they make it and we had one of the strangest experiences I've seen on a brewery tour talking to they guy in charge of it. We only got as far as the outside of the building in which it's made and most of our questions were nervously answered with "I can't tell you that". The smart money was on it being dealcoholised by reverse osmosis. The lack of alcohol means it gets 80 PUs. In Ireland you can get Guinness Zero on draught, an opportunity I did not take up as you can also get Guinness draught on draught. 

In the traditional Irish manner the lauter tuns are called kieves on the information display but they seem to have forgotten when making the banners. 

Whatever you call them though they're bleedin' huge. They make 7 million hl a year of beer at high gravity. Which I think it's fair to say is lots. There are three Steinecker brewing lines, the Guinness one making 1000hl at a time from 20 tonnnes of grist, 11 times a day. The ale and lager (Smithwicks, Harp, Hophouse, Carlsberg) goes at the same rate but with a brew length of 650hl. Due to demand some Guinness is also made on the ale and lager line. Lastly there's a roast malt barley extract stream. Given the awkward experience with the Guinness Zero guy I didn't ask about the Guinness Flavour Extract so the secret of the ooze will stay secret. 

They have four roller wet mills, Mash Conversion Vessels (MCVs), Lauter Tuns, Kettles and Whirlpools. The barley used is all Irish, Planet being the current malting variety with presumably feed barley for the raw and roast barley. The weak worts are recycled. The roast barley is unmilled and adds colour, flavour and aroma. The roast malt extract is combined with the Guinness stream in the kettle for a one hour boil. 

They mash in at 64.5°C rising to 72°C. There are two MCVs and one lauter tun for each stream. 

Fermentation takes two and a half days at 22°C with the ABV reaching 7.2%. The yeast is used for eight generations. They have 100 tanks ranging in size from 1200 to 4000hl. 

The roast house uses converted three tonne coffee roasters. They have bigger blades as barley grains are smaller than coffee beans. They are indirectly heated up to a maximum of 232°C (that's only for 90 seconds!). The last 20 minutes in a process taking two and a half hours are critical. The roasting chamber has water sprayed on at the end of the cycle to lower the temperature immediately. We were told 10% of the grain is roasted (though I'd heard 8% before) but my mind really got to boggling when I heard it's 20% in FES. It definitely has a darker head then draught Guinness. It will be as Guinness Flavour Extract that's added though. FES also has three hop additions. Probably extract there too mind. 

Fifty or so breweries worldwide produce Guinness under licence and samples from all of them are sent to Dublin for analysis. The lab has lot of shiny kit and sensory analysis also takes place by a 12 strong panel of trained tasters. They also deal with RTDs and the spirits Diageo makes for Africa. Local raw materials such as sorghum, millet and maize can be used and they have to be careful about Phenolic Off Flavours (particularly with sorghum) as the Guinness yeast is POF+. The limit for 4VG and 4VP is set at 0.25mg/l as that's the flavour threshold for most people. And they may allow a lot of diacetyl but they keep acetaldehyde low. 

pH and total acidity as acetic acid is measured. The haze meter uses 90° light at 650nm, they need to use a smaller cell for stout than lager though! 

Sorghum in particular is high in oxalic acid which can lead to beer stone problems. They measure calcium content, treat with nitric acid and measure again to show calcium oxalate. Not entirely sure how that works but give me the SOP and I'd have a go. 

The pilot plant was spread over four floors with of course the hammer and roller mills at the top. 

They have 10hl and 5hl breweries, which use 300 and 90kg respectively. 

They have a mash filter as well as a lauter tun. Wort's heated with an external calandria. 

The keg filler will go at 30 kegs/hr and they have a hybrid can and bottle filler. 

As Guinness supplies the UK from Dublin a lot of beer is tankered out: 60-65%! Forty 300hl tankers a day leave the site, most going to Runcorn, some to Belfast. They can fill a tanker in 45 minutes. 

That was the last brewery I went to on the Irish study tour and they really had left the best till last, it was fantastic. But did it make the best Irish stout? More on that later. 

A visit to Schlenkerla brewery

As with previous study tours I was once again surprised by which brewery turned out to be my favourite. Which just shows the importance of research.

The Schlenkerla brewery got its name because the original owner would flap his arms around when walking, which apparently made him a "shlenkerla". Who'd have though you'd need such a word? Not me that's for sure, but the next time I see someone in the street flapping their arms around I'll be ready.

Bamberg's nice

The brewery may go back to 1405,

They make their own malt (to a colour of 15-20 EBC) using beech wood though someone on the tour  less gullible than me did point out it's rather small for the amount of beer they make.

The brewhouse is a two vessel system: a mash/wort kettle and a lauter tun. The lauter tun is raised so it can run off under gravity.

They decoct the thick part of the mash twice except for the helles which only has one decoction. The mash is for three and a half hours, lautering  three hours and boil one hour. They mash in at 50°C and mash out at 78°C, the wheat beer is mashed in at 40°C.

The brewery runs for 24 hours Monday to Thursday, with three brews a day. They use 950 kg of malt and three kg of hops for a brew length of 50 hl.

They use untreated town water which is best for the darker beers. Three styles are brewed all year round and seven in total, including a bock in October and a dopplebock in December. Märzen makes up 80% of production. The weiss beer is top fermented. The märzen has an original gravity of 13.5°P (54°S).

The copper parts of the brewery date from 1936, the stainless steel from 1980 and the automation from 1993.

They have sandstone cellars which date from at least 1387. The cellars are at 10°C all year round that makes them great for lager fermentation.

I think that makes them yer proper caves where lagering can have taken place back in the day before refrigeration. Course they have refrigeration now: fermentation starts at 8-9°C and the beer is chilled to 5°C when 3°P (12°S) is left followed by a week where a free rise to 6.5°C is allowed for a diacetyl rest before chilling again to 2°C for four weeks for the märzen and longer for stronger beers.

In their own pubs they sell beer in wooden casks

All beers are filtered except for the wheat, lent and Summer beers. The wheat beer has speise added.

The coveted IBD plaque

It was a fantastic brewery and I've even started to like smoked beers more. After the brewery tour we got to explore some caves.

A rather brave decision from the tour organisers I thought. Fortunately there was only one casualty.

It was great seeing the caves, there were even more impressive than those found in Dorking.

The tunnels had had various uses over the years. Wine was stored in them, then beer once bottom fermentation arrived.

After artificial refrigeration was invented they were not needed for beer.

They were used as an air raid shelter during the second global mass imperialist slaughter, though the bombing of one cave still lead to the death of 54 people.

There was still a little bit about beer in the caves:

Then we got to go to a bonus brewery for which my notes are sadly lacking.

And then, as if we hadn't had enough already, it was time for a beer tasting. No one said this Continuing Professional Development would be easy!

With that the study tour was over and here ends a chapter, but a chapter only, of the history of the revolutionary proletariat of the sea. No, hang on a minute that's not right, that was a century ago in the North of Germany. Our tour of Bavaria had finished though. Next year a trip to the Brett fest looks likely and the year after the next proper tour will be hopefully be to Boston. I'm looking forward to it as I've heard tales from travellers of strange and exotic beers made in barbarian lands which will be interesting to discover.