Continuous Pumping Of Fermenting Wort To Reach Fg Faster?

[Bandito]

I have had a theory for a while now, that if wort could be pumped continuously during fermentation, that it would ferment fast without producing any off flavours.

The purpose is to reduce fermentation times. As I am setting up a new rig, I am trying to size the fermenter. If the time can be reduced I could make do with a smaller fementer(s). I would be expecting 1 week instead of 2 weeks to reach FG.

The setup would idealy be a conical fermenter with a peristaltic pump mounted in the wall of a fridge with the motor hanging out in the open air for lagers, And no fridge for Ales. Noise from the pump might be the biggest issue.

Before I go to the effort of testing this, please tell me, would this work? Planning on a pump sprayer test fermenter mabee as low as 1 L for the test setup.

Edit: To clarify a bit more: Taking a chemical perspective, the rate of a reaction is influenced by both temperature and surface area. If the temperature is the same, the only option is to increase the surface area. Borrowing from the magnetic stirrer, constant movement of the wort by pumping should increase the surface area by not allowing it to form a thick bed on the bottom.

 

[QldKev]

by pump do you mean pump o2 into the wort?

 

[swilks]

Like a yorkshire square type arrangement?

 

[bradsbrew]

What about some sort of (gentle)stirring mechanism attatched inside the fermenter?

 

[unrealeous]

Don't forget to take out your patent if it works, and make sure you keep it top secret

http://www.freepatentsonline.com/3911139.html

 

[Bandito]

by pump do you mean pump o2 into the wort?

No, just pumping the fermenting wort

Like a yorkshire square type arrangement?

Edit: I dont think so, but am still researching what that is - looks like it designed for faster fermentation of ales? Linky's - http://en.wikipedia.org/wiki/Yorkshire_Square
http://www.google.com.au/search?hl=en&...oq=&gs_rfai=

What about some sort of (gentle)stirring mechanism attatched inside the fermenter?

Probably the same thing, but more powerful and turbulant - sucking the yeast cake from the bottom of the fermenter, breaking it up in the peristaltic pump, perhaps with a sieve on the outlet to ensure yeast clumps are small.

Don't forget to take out your patent if it works, and make sure you keep it top secret

http://www.freepatentsonline.com/3911139.html

I wont tell anyone if you dont! Thats the wierdest patent ever - relating to suck a narrow range of specific temps and alc. concentrations? Wine perhaps! Must have been a gap in other patents. (great example of how not to write a patent!).

Schmatic: The returning wort would be pumped back in below the top of wort level to reduce airation, as the nornal airation would be done before.

 

[Bribie G]

Yorkshire Stone Square system rouses and pumps the wort because the yeast is highly flocculating and prefers to stick together rather than produce beer. On another tack, here's a very interesting and radical passage from my ever faithful Encyclopedia Britannica 1911 edition which will no doubt horrify many people but it obviously worked a hundred years ago:

It is a sign of the times and further evidence as to the growing taste for a lighter type of beer, that lager brewing in its most modern form has now fairly taken root in Great Britain, and in this connexion the process introduced by Messrs Allsopp exhibits many features of interest. The following is a brief description of the plant and the methods employed:—The wort is prepared on infusion lines, and is then cooled by means of refrigerated brine before passing to a temporary store tank, which serves as a gauging vessel. From the latter the wort passes directly to the fermenting tuns, huge closed cylindrical vessels made of sheet-steel and coated with glass enamel. There the wort ferments under reduced pressure, the carbonic acid generated being removed by means of a vacuum pump, and the gas thus withdrawn is replaced by the introduction of cool sterilized air. The fermenting cellars are kept at 40 F. The yeast employed is a pure culture (see FERMENTATION) bottom yeast, but the withdrawal of the products of yeast metabolism and the constant supply of pure fresh air cause the fermentation to proceed far more rapidly than is the case with lager beer brewed on ordinary lines. It is, in fact, finished in about six days. Thereupon the air-supply is cut off, the green beer again cooled to 40 F. and then conveyed by means of filtered air pressure to the store tanks, where secondary fermentation, lasting three weeks, takes place. The gases evolved are allowed to collect under pressure, so that the beer is thoroughly charged with the carbonic acid necessary to give it condition. Finally the beer is again cooled, filtered, racked and bottled, the whole of these operations taking place under counter pressure, so that no gas can escape; indeed, from the time the wort leaves the copper to the moment when it is bottled in the shape of beer, it does not come into contact with the outer air.

I have an aquarium air pump and heck I'm going to try it be-buggered.

 

[Bandito]

Although I know ale yeast are called 'top fermenting', to be honest I have never actually used one, but was considering it for this experiment, but I'll stick with the bottom fermenting lager yeast I know. Seems like I need to drill a hole in the fermenting fridge for the peristaltic pump motor to poke through for cooling afterall. I'll try one with continuous pumping, and one without from the same airated and inoculated wort that I'll make this weekend.

Great excerpt the Bribie, always fun to read stuff from long ago and see how they thought about things. Does sound like a recipe for oxidised beer though. Sounds like the fresh air might have been part of the temperature control?

 

[thelastspud]

I thought that with a conical fermenter you had a current anyway, i.e. in the middle it is slightly hotter from active fermantation so the dormint yeast falls down the cone gets woken up by the temp and raises through the middle of the fermentor hits the top falls down the sides and it all starts again. Dont know where i read this though, maybe the idea has fallen out of fashion

 

[katzke]

Ever watched what happens during active fermentation? Not sure if it is the same with lager yeast. Ale yeast has a very turbulent fermentation at peek activity. Can not see how stirring it up any more would help.

Plus lots more goes on with fermentation then just the yeast eating sugar and getting drunk. I see no reason to mess with the process as I have found my ale has gotten better after I learned to leave it alone for at least 3 weeks.

It may be different with lager yeast and I am sure you will try it out. Best to do a double test and have it scored by competent tasters to get feedback.

 

[Wolfy]

I'm no expert but I'd question the logic behind the suggestion - and I'd trust the input of those more educated in all matters beer/yeast more than myself - but I'm a little skeptical about the process.

Yeast fermentation is a biological not a chemical process. During fermentation yeast consume the available sugars and will flocculate as yeast cells die or the sugar supply is depleted. In addition the first stages of fermentation often produce unwanted byproducts that are 'cleaned up' later in the fermentation process, by speeding up the duration you may find that many of those by-products end up in your end beer.

Using a stir-plate to grow yeast works well due to the continuous aeration which provides yeast with the constant oxygen supply they need to reproduce. However fermentation is anaerobic and aerating your fermenting beer (pumping it around in the open air) is going to cause oxidation issues, and if the yeast population is already large enough, is not going to speed up fermentation.

In addition trub, krausan and the sides of the fermenter collect many off-flavours/compounds and I'm not sure that continuously mixing these, along with dead yeast cells, will do much for the flavour of your beer.

The only advantage I can think of is that continuous mixing - if you could do it without aeration - might allow fermentable sugars to be more readily available to the yeast, however even without mechanical intervention an active ferment creates a fair amount of mixing. By the time yeast has started to flocculate it's because the sugars have been depleted, so while mixing would not allow the formation of a yeast-cake thus making any remaining sugars more readily available to the continuously-mixed-yeast, the theory also has a number of disadvantages - especially I think in terms of the quality and taste of the end product.

By pitching the 'right' amount of active and well aerated yeast - grow it on a stir-plate using the exact same wort - you could short-cut the lag period and respiratory phase and the yeast can kick off fermentation almost immediately, this would leave the fermentation duration to depend mostly on the yeast strain and wort characteristics. This would - I think - do more to speed-up fermentation of a good tasting beer than continuous mixing, however the mixing-process would grow yeast cells well and may also result in slightly reduced fermentation times.

It's my uneducated-feeling that fermentation-duration is going to depend more on the yeast strain and wort characteristics (alcohol tolerance, gravity, available nutrients etc) than mechanical mixing. For example I find my re-cultured Coopers-yeast in a typical Australian Ale, is done and dusted within 2-3 days but leave it about 7 to ensure it's complete and for any un-wanted products to be consumed. I can't speak for many Micro's but know one ferments in primary conical's for a week before secondary/cold storage, so with yeast and ingredient selection, I'm sure you could do the same - if that is the objective.

 

[QldKev]

I'm no expert but I'd question the logic behind the suggestion - and I'd trust the input of those more educated in all matters beer/yeast more than myself - but I'm a little skeptical about the process.

Yeast fermentation is a biological not a chemical process. During fermentation yeast consume the available sugars and will flocculate as yeast cells die or the sugar supply is depleted. In addition the first stages of fermentation often produce unwanted byproducts that are 'cleaned up' later in the fermentation process, by speeding up the duration you may find that many of those by-products end up in your end beer.

Using a stir-plate to grow yeast works well due to the continuous aeration which provides yeast with the constant oxygen supply they need to reproduce. However fermentation is anaerobic and aerating your fermenting beer (pumping it around in the open air) is going to cause oxidation issues, and if the yeast population is already large enough, is not going to speed up fermentation.

In addition trub, krausan and the sides of the fermenter collect many off-flavours/compounds and I'm not sure that continuously mixing these, along with dead yeast cells, will do much for the flavour of your beer.

The only advantage I can think of is that continuous mixing - if you could do it without aeration - might allow fermentable sugars to be more readily available to the yeast, however even without mechanical intervention an active ferment creates a fair amount of mixing. By the time yeast has started to flocculate it's because the sugars have been depleted, so while mixing would not allow the formation of a yeast-cake thus making any remaining sugars more readily available to the continuously-mixed-yeast, the theory also has a number of disadvantages - especially I think in terms of the quality and taste of the end product.

By pitching the 'right' amount of active and well aerated yeast - grow it on a stir-plate using the exact same wort - you could short-cut the lag period and respiratory phase and the yeast can kick off fermentation almost immediately, this would leave the fermentation duration to depend mostly on the yeast strain and wort characteristics. This would - I think - do more to speed-up fermentation of a good tasting beer than continuous mixing, however the mixing-process would grow yeast cells well and may also result in slightly reduced fermentation times.

It's my uneducated-feeling that fermentation-duration is going to depend more on the yeast strain and wort characteristics (alcohol tolerance, gravity, available nutrients etc) than mechanical mixing. For example I find my re-cultured Coopers-yeast in a typical Australian Ale, is done and dusted within 2-3 days but leave it about 7 to ensure it's complete and for any un-wanted products to be consumed. I can't speak for many Micro's but know one ferments in primary conical's for a week before secondary/cold storage, so with yeast and ingredient selection, I'm sure you could do the same - if that is the objective.

Very well said, I think what you have put forward is correct.

I don't think continuous aeration would be beneficial; but for early stages of fermenting, as BribieG mentioned, if you had a highly flocculating yeast recirculation could keep the yeast active and ensure you don't get a stalled ferment; and minimise the fermentation period, minimising chances of off flavours. But as you mentioned I think you would need to allow a clearing period without the turn over.


QldKev

 

[Swinging Beef]

http://nzic.org.nz/ChemProcesses/food/6A.pdf

If you hasnt seen it before.

 

[MHB]

Back in the 80-90's the Kiwis spent a lot of time and money on all sorts of bizarre brewing methods, like continuous mashing and continuous fermentation like in that article from 2002 The trouble is it hasn't really progressed far from then, in fact, in spite of the obvious advantages offered I think most of those plants are back to doing things the old way.

There might be a clue in there for those who think about it.
MHB

 

[justsomeguy]

Back in the 80-90's the Kiwis spent a lot of time and money on all sorts of bizarre brewing methods, like continuous mashing and continuous fermentation like in that article from 2002 The trouble is it hasn't really progressed far from then, in fact, in spite of the obvious advantages offered I think most of those plants are back to doing things the old way.

I think the main issue with the continuous fermentation thing was supposed to be sanitation. My understanding is that, if you got a bug in there then the whole thing would come to a screaming halt very very quickly. I also think its a case of 'living on the edge'. The process works but minute changes in the system can cause massive problems necessitating throwing out the whole batch .

I think there is a Brewing Network Sunday Session episode where they talk to a NZ guy who actually worked on a continuous fermentation system commercially.

gary

 

[katzke]

Continuous fermentation and stirring the wort are 2 different things. Least from what I got out of the article they are.

Plus you have to remember that big breweries have labs on site so they can monitor every yeast fart if they want to. Dang now Bandito will design an automated home brewing laboratory.

 

[Sammus]

Back in the 80-90's the Kiwis spent a lot of time and money on all sorts of bizarre brewing methods, like continuous mashing and continuous fermentation like in that article from 2002 The trouble is it hasn't really progressed far from then, in fact, in spite of the obvious advantages offered I think most of those plants are back to doing things the old way.

There might be a clue in there for those who think about it.
MHB

I guess there's a reason it hasn't progressed far, right? Surely that reason isn't because it worked so well and made a much better beer... kinda reminds me of BIAB and no-chill

 

[Bribie G]

With the rise of Megabreweries in the UK in the 60s they also did research into continuous fermentation. The attached extract shows an interesting design that could be attempted at home if you were a total screaming anorak as well as a competent SS welder. And had a 20 foot ceiling I don't think any of the methods took off in the UK - they went on to other weird stuff like hydraulically squeezing the spent grain to get the last few degrees out of it, etc.

 

[Nick JD]

I read somewhere that continuous fermentaion has pH issues that have to be dealt with. Also yeast removal.

The OP's asking about increased speed via mixing ... I'm not sure you'd double fermentation time, but you'd probably get rid of that pesky pissing about that most yeasts do in the last 10% of SG (I guess that's when they have to wait for some sugaz to come to them and the alcohol is making them sleepy).

Another way to half your fermentation time is to brew at 27C. Quick as! BUBBULE BUBBLE BUBBULE BUBBLE BUBBULE BUBBLE BUBBULE BUBBLE BUBBULE BUBBLE STOP.

 

[Bribie G]

Yes Nick reminded me: some yeasts actually go well in the mid 20s, a cracking example is Wyeast Irish Ale. Guinness in Dublin ferment at 25 degrees and they crank out the beer in 2 days. I guess the Wyeast one must be historically related because my first Irish Red had a runaway fermentation and I had no ice bottles due to fridge dramas. It flew through the ferm in 3 days then the beer surface was calm as a millpond. So I kegged and bottled and it was beeoootiful Irish Red. I sent a bottle to Rde, he may concur.

Now I use that yeast for all sorts of other darker beers such as brown ales and stouts and it goes like the clappers. I reckon it would make perfect APAs and AAs as well in less than a week.