'square' fermenters

[lael]

In BLAM and in some reading on Yorkshire squares, both mention that yeasts produce different tastes when the fermenter shape is more 'square' or shallow in cross section than modern fermenters, which tend to be cylindrical.

Does anyone know what flavour differences the different shapes actually create?

 

[kelbygreen]

most likely it will taste like a block instead of a cylinder :lol: But no I am not sure and in a home brew setting and all variables I would find it hard if you could do a side by side and tell the difference. what about triangle fermenters

 

[tavas]

Was the reference for open top fermenting?

 

[mje1980]

I used a cheap plastic storage tub ( biggest I could fit in my small ferm fridge ) to ferment a porter. It was very nice. I keep meaning to do it again, though it's a bit of a hassle. You should only leave it uncovered for the first 48hrs or so, then transfer to a sealed fermentor. Use a top cropping yeast and collect some of the thick creamy yeast, it's great stuff.

 

[mje1980]

The height to width ratio apparently has an effect on the ester profiles given off by the yeast. It just needs to be wider than it is tall.

 

[lael]

Thanks mje, could you tell a difference from a tall fermenter? Did you end up doing the same recipe in a 'normal' tall fermenter?

The brew like a monk reference I think was from st sixtus (of westy 12 fame). When they put in tall Conicals, the flavour profile changed and they had to tweak the recipe / processes to get it back.

So it got me curious... What are the actual differences?

 

[mje1980]

No side by side mate though I really liked the ester profile. Could've been all in my head. Nice porter either way haha. Fermentor geometry is also mentioned in the "yeast" book. Mentions that there is a definite effect on final flavour. I need to try it again I think and do a side by side.

 

[Yob]

Overall it sounds like it would be less rounded...

Sorry...

 

[Feldon]

And a slight rectangularity on the middle palate.

 

[Mardoo]

This is one of those things I often wonder about and have never found laid out anywhere. Subscribed.

 

[4KingAle]

Obviously talking about very large fermenters. Where the yeast would struggle makng its way through such a large column.

 

[lael]

Lol, loving the joke

Does the yeast book mention how the flavour profile is affected or just that it is?

 

[luggy]

Lol, loving the joke

Does the yeast book mention how the flavour profile is affected or just that it is?

Reading this at the moment, it doesn't go into detail just that it changes the character of the beer

 

[mje1980]

There was a PDF floating around the interwebs about an actual study I'm sure. Been a while but there was something about wider fermentors giving much more surface area exposed to oxygen, which in turn put much less stress on the yeast. I can say that I got a very nice thick later of tan mousse like yeast on top, which is collected obviously.

I've recently got some smaller cubes the fresh wort kit 15 litre ones. I'll do a double batch to fill them with a mild or porter and ferment them one after the other. One in the square and one in my normal fermentor.


For me, it is a lot of stuffing around, and wasteful, as my "square" only fits around 12 litres, so I end up with 5 or 6 litres of spare wort. I'd normally add that to a 10 litre fermentor and hit it with brett, but I have 3 of those already full so don't really want anymore fermentors laying around the house ( 5 inside the house already ).

 

[Cervantes]

I'm watching this with interest.

I currently ferment in 20 litre jerry cans, which are proportionally tall and thin with a small surface area.

In the past I've used the traditional plastic fermentors and also experimented with pressurised fermentation in Cornelius Kegs.

I can't say that I've noticed a huge difference in any of the results, apart from the carbonation from the pressurised fermentation of course.

Edit: Spelling

 

[sean_0]

In BLAM and in some reading on Yorkshire squares, both mention that yeasts produce different tastes when the fermenter shape is more 'square' or shallow in cross section than modern fermenters, which tend to be cylindrical.

Does anyone know what flavour differences the different shapes actually create?

The shape of the fermenter might have an effect, but surely not as large an effect as the rousing they do in Yorkshire squares. Here's an interesting blog post about it: http://barclayperkins.blogspot.com.au/2008/11/three-systems-of-fermentation-1880-1914.html

 

[technobabble66]

Based on no actual knowledge, but:
I'd guess there's a difference in O2 exposure at the start (mentioned above), CO2 elimination and overall reduction of liquid pressure at the lower layers.
The first 2 would result in much less stress to the yeast, and pressure fermented beer is meant to have a v clean finish I believe - ie: lower esters (?).
So it could be the lower overall pressure that allows good ester development, whereas the other 2 gas exchange factors just produce a nice clear/quality ester profile rather than a muddled jumble of good and bad esters.

Just speculating.

 

[Bribie G]

Blacksheep Brewery use modern Yorkshire Stone Squares that are metal and round.

 

[kaiserben]

This topic is very interesting.

I ferment in 10L jerry cans. At the moment I'm doing a series of ESBs.

I've noticed there is rarely any krausen and a lot of the fermentation activity doesn't occur at the top (for example I usually see a lot of activity just under where the jerry can's handle comes in, which in the grand scheme of things is actually very near the bottom of the vessel. I see the yeasts zipping around like crazy and what I assume is CO2 bubbles accumulating under where the handle comes in). Here's a vid to demonstrate where I mean: https://www.facebook.com/video.php?v=10152907880672959&l=2549932669226074719

I've been a bit disappointed in the yeast/ester characteristics in these final beers. So much so that I've been suspecting infection on first tastings, but then a few sips later start thinking it's just high-temp esters characteristics. Basically I can't put my finger on the cause. Ferment temps have been at the higher end of the scale (certainly over 20C and possibly 22 or 23C using M79 and S04. Sadly, I don't have a ferment fridge).

On the contrary, I fermented a Schwarzbier with a San Fran Lager yeast (WL810) in one of these jerry cans and it was perfection (for this one my ferment temp was all over the place, from 10C to 20C). So, I dunno, maybe it's not great for top fermenting yeasts but is fine for bottom fermenting?

 

[MHB]

The "Old" and I mean really old Yorkshire squares were made of slate, they stopped doing that as soon as a viable alternative was found (i.e. Stainless). The point of the design was that the yeast was very flocculent and had a bad habit of stalling out, the "squares were designed so that the foam from the krausen would fall back down the side and rouse the yeast, keeping it going until the beer was fully attenuated.
These days the squares are mostly round and as Bribie said made of stainless, they are also fitted with a parachute (also made od stainless), to cause the same wort recirculation.

From a home brew perspective height of the fermenter isn't really going to be an important issue. if you were a Mega Brewer with 90M tall fermenters brewing over-gravity (at say 1.070) beer the pressure on the yeast at the bottom of the fermenter would be around 940kPa, (P=Density x g x H in M) that will affect how the yeast preforms, but unless you have a several meter tall fermenter I personally doubt the pressure will play much of a roll in the flavour.

If you want to get the most from Yorkshire Yeast its a good idea to give it a good rouse especially as the ferment starts to slow, I have sat a glass fermenter on a magnetic stirrer and given the works a good spin every couple of hours on day 3-5, seemed to work OK, but so did a sterilised spoon...

Mark