No, it's not a Yorkshire square

It's a tradition, or an old charter, or something that wheneven someone who knows a bit about beer sees an open square fermenter they ask "is that a Yorkshire square?". The answer is nearly always, no. 

Open fermenters are the exception not the rule nowadays so it's usually only in old breweries that you see them. The fact that a fermenter is open and not round does not make it a Yorkshire square though. Actual Yorkshire squares are considerably stranger. If you can see a fish tail it might be a Yorkshire square, but only if the vessel is divided by a deck too. 

Diagram of a Yorkshire square fermenter

Cross sectional diagram of a Yorkshire square

They were originally made of stone, and the ones I saw at Sam Smith's were made of slate. They have been made of stainless steel though, which I think they had at Tetley's, and there are stainless round ones (Yorkshire rounds!) at Black Sheep. 

They have a lower level separated from the upper level by a deck. The deck has pipes known as organ pipes running down to the lower level, and a large opening with a flange around it. They were mainly, but not exclusively, used in the north of England. I guess the clue's in the name with that one!

An empty Yorkshire square showing the upper deck

They were developed to work with highly flocculent ale yeasts, i.e. yeasts that rapidly clump together and rise to the top of the fermenter. 

Yorkshire squares being roused at Sam Smith's

The lower compartment of Yorkshire squares is filled with wort and yeast, and so is an inch deep layer on the upper deck. During fermentation yeast rises through the large opening and beer drains back into the lower compartment through the organ pipes. 

Yorkshire square in use

Rousing is used to keep the highly flocculent yeast in contact with the beer - the beer is recirculated by pumping it through the fish tail on to the upper deck. At the end of fermentation the yeast can be skimmed from the deck. 

As well as being a way of fermenting with, and collecting, highly flocculent yeast Yorkshire squares are also said to make beers with a fuller palate than beers fermented more conventionally. 

I'll end on a video one being roused:

Guinness CAN organise a piss up in a brewery

Shortly before I went round Guinness' Open Gate brewery in London The Guardian did a hatchet job on it. For some reason restaurant critics put the boot in more than any other type of reviewer. Though as the only restaurant reviews I ever read are when a scathing one goes viral on social media I guess the reason why is pretty clear. 

I was going to the brewery as part of the CIBD Southern section's AGM, but first we had to do the business part to do at Diageo's HQ. 

It's as posh as a posh thing, but at the bar Guinness is only £2.80 a pint. Don't get ideas though, you have to get past security to get in. And anyway, at CIBD events I normally pay nought pounds and nought pence per pint so it seemed a bit steep to me. 

Before business, Steve Wilkinson, who's worked with and for Guinness, went through a fascinating history of Guinness and his own part in it.

There was a bit of juicy gossip that the Guinness family had wanted to sell the company before Ernest Saunders became the chief executive. But they hadn't controlled enough shares to make it happen. I had read previously that after the takeover of The Distillers Company their shares were diluted to the point they no longer had a seat on the board. They're still immensely wealthy though, the current head of the family lives on an estate over 35 square miles in size. That's 2.6% of Suffolk. I don't think my house is even 2.6% of the bleedin' road!

After business and little light networking (two pints worth for me) we hoofed it over to the Open Gate Brewery. There's quite a lot to it. The parts we saw were the porter's loft, and of course the brewery. 

The brewery is enter AND exit via the gift shop. The brewery is a marketing exercise more than anything else. But hey, marketing budgets are massive!

The 15hl/9bbl brewery from BrauKon had all the bells and whistles. It's four vessel brewing system, but we didn't get near it, so no pictures of the inside of the lauter. They mostly use pellets but have a hop back too if they want to use whole hops. They can also move mash backward and forwards so can do decoction if they want to spend eight hours mashing instead of one. They're currently brewing twice a day, but could double that. 

Brewing vessels at the back there, yeast tanks behind the brewer

There's a four vessel CIP (Clean In Place) set, and an effluent plant for controlling temperature and balancing pH. 

CIP vessels behind the brewers

They have 4 x 15hl, 6 x 30hl and 4x60hl fermenting vessels. Though there is a core range of beers the focus is on innovation and the brewers have a lot of freedom in deciding what is brewed. 

There's a flash pasteuriser (11-15 pasteurisation units), a lenticular filter, a centrifuge and buffer tanks. So unsurprisingly there's no beer served as god intended, it's currently all kegged and will be canned once the canning line is commissioned. 

The centrifuge

There's reverse osmosis treatment for the brewing liquor, with mains water blended back in and salts added as required.

They're currently using the Guinness ale and lager yeasts, but they can propagate yeast from slants if they want to. 

Despite the brewery being large for its modest brewlength it was more a stand and point than a tour, and we didn't stay there long. 

Then it was up the escalator and back to the gift shop. The building used to be an H&M and they've kept the escalators. First time I've seen them in a brewery!

After the brewery tour it was time to see if Guinness could organise a piss up in a brewery. And the answer was of course, yes. 

I don't know what deal the CIBD had done with Diageo or if we were subsidised, but we paid a tenner. This gave us pie and mash, which was nice, and a pint of Guinness (brewed in Dublin). I was keen to have somethng brewed on site though, so I had a hazy IPA next, which was nice enough. I think the ABV was a bit hefty, as on top of the three pints of Guinness I'd had I was defintely feeling pissed by the time I'd fininished it. So there you have it.

The Guardian journo's main complaint seemed to be that you had to take a lift to the toilets. Which did make me wonder what she'd think if she ever went to a Wetherspoons. The building we were in had the fourth floor button in the lift labelled toilets. But the first floor bar we were in had a toilet, so I had no trouble getting rid of the beer I'd rented without using the lift. 

I don't know how my experience and tour at the Open Gate Brewery compared to the ones for you pay for, but I enjoyed myself. Which I guess blows my chance of becoming a restaurant critic.