Step fermentation idea- can this work?

[Droopy Brew]

So, I dont know if this has been done before or discussed however I was having a think the other day about progressively stepping up the volume of a ferment to grow the yeast in proportion.


Take a lager for example, a great beer to brew no chill due to the low hop profile but requires an very large pitch of yeast to get a good ferment. This can be expensive in both time and money.

Im brewing batches of about 45L so a 5% lager would require about 8-10 smack packs or 5-6 L of starter (I haven't done the calcs but lets go with these numbers).

So Im thinking, when i no chill, I drain into 3x 15L cubes that I have saved from FWKs. If I were to start the ferment off with a single 15L cube, I could pitch say 1L of starter or 1-2 packs of dry yeast at good pitch rate (again, not calculated but approximate). Then say a day after ferment starts the yeast should have grown in numbers to allow the second cube to be added. This would be close to high krausen too so should really take off. It would also keep the yeasties in a growth phase. Another day or 2 and the final cube can be added and ferment out as normal. Essentially this is doing a stepped starter during fermentation on a bigger scale.

I currently ferment in a 50L keg with a coupler under pressure. Obviusly I would not pressurise until the final cube was introduced. I would also keep the cubes in the fermentation fridge so they are at the same temp as the fermenting wort.

So firstly- has anyone done this and if so did it work?
What are the issues with this? I imagine oxidation is probably not an issue with the second cube as the yeast is in a stage where extra O2 is probably a good thing. Will it become a problem with the addition of the 3rd cube? Im sure a syphon transfer would negate any real issues. (which I do anyway due to the small opening of a 50L keg)
I guess infection chances would be a bit higher given the fermenter is opened a couple of times for a reasonable amount of time. I would hope the vigorous yeast activity and high numbers would out compete any potential airborne yeast cells.
Probably other things I have missed, feel free to point them out.

And go....

 

[Bribie G]

Drauflassen

 

[Droopy Brew]

So what you're saying is there's a German app for that?

Thanks Bribie, now I have a name for it, I did a quick search and found some info on it.

So my next question- I proposed to do this in 3 stages, perhaps 2 would be enough ie. 15L then add the extra 30L in that 24-30hr window.
I guess the deciding factor is if there are enough yeast cells after that period in the 15L 'starter' to be a sufficient pitch rate for 45L.

Obviously that depends on the initial cell count in the first 15L but is there a calculator available which can determine this? It would need to take into account initial yeast cells, growth rate and time. Thinking I may be able to *******ise the Brewers friend yeast calculator however growth rate per unit of time might be out of wack.

 

[Dave70]

LDME is about what, $10 per kilo? So 6 liter starter including the yeast will run you under 20 bucks. Am I missing something here?

 

[mtb]

LDME is about what, $10 per kilo? So 6 liter starter including the yeast will run you under 20 bucks. Am I missing something here?

A whole batch can cost $20 - $40 for malt & hops alone, $20 for that much LDME is a fair whack in comparison.

 

[Bribie G]

If you get onto Braukaiser I'm sure there's info on Drauflassen. In their case they have a big fermenter but smaller wort production facilities. You have a big fermenter with plenty of wort, but it strikes me as being a similar outcome, i.e. breeding up the yeast between wort additions whilst keeping a good cell count (average).

LDME is about what, $10 per kilo? So 6 liter starter including the yeast will run you under 20 bucks. Am I missing something here?

Erm I don't think the OP mentioned LDME
He's just adding three doses of already-produced wort to step the volumes up whilst growing yeast at each stage, to keep in step. Basically the same as the German Drauflassen. Here you go Droopy: that Braukaiser ref

 

[MHB]

Yeast needs Oxygen to reproduce successfully, without the O2 it will deplete it's reserves of glycogens, sterols trace elements, add O2 when you add the wort and you run into problems with oxidising the wort.
Yeast that has depleted its reserves is described as being less Vigorous (the other half of Vitality and Vigor (health and population)) odds are you will get lower attenuation, more side issues (esters and higher alcohols, diacetyl), poor yeast flocculation... all the usual problems associated with under pitching or pitching unhealthy yeast.
Mark

 

[manticle]

My understanding of draflaussen recommends oxygenating the to be added wort first, not the whole batch.

 

[Droopy Brew]

LDME is about what, $10 per kilo? So 6 liter starter including the yeast will run you under 20 bucks. Am I missing something here?

Yes. Time.

 

[MHB]

Just went and read the Braukaiser (link above), might be a bit easier than I would have thought, especially for no-chill stored wort.
Getting the second/third wort well aerated would be important to avoid yeast stress.
Timing of your wort additions would be important, you want to keep the yeast in its growth stage, rather than have it switching back and forth between making yeast and making alcohol.
Personally I would make enough yeast to pitch the whole wort up front.
Mark

 

[Droopy Brew]

And I had you pegged as someone that was for experimentation
Agree that timing will be of the essence. Understanding the yeast phases and when to introduce the wort will be key. An O2 stone in the cubes will do for aeration. I reckon it will be worth a go and am fairly optimistic that it will be a rather forgiving process and work quite well. Will give it a go in the new year.

 

[S.E]

I haven’t no chilled for a while but when I did standard practice was pour one cube in to a 60L fermenter and pitch 1 packet of dry yeast or a smack pack. Next morning within 16-20 hours pour two more cubes in shaking and splashing as much as possible.

 

[MHB]

We would have to have a long talk about what you mean by experimentation.
I'm all for exploring possibilities, but in a way that the results are meaningful, repeatable and measurable. Probably why I have so many problems with some of alleged experiments.
Mark

 

[Hpal]

Drauflassen

 

[Garfield]

If you have a few fermenters on hand you could look at blending.

If you have enough yeast for cube 1 you could ferment through (including higher temp diacytel rest) then rack to another vessel. The yeast cake left behind should be ample to then ferment the remaining 30 L then rack onto first batch and begin lager phase if desired.

Probably less infection risk this way too

 

[S.E]

If you have a few fermenters on hand you could look at blending.

If you have enough yeast for cube 1 you could ferment through (including higher temp diacytel rest) then rack to another vessel. The yeast cake left behind should be ample to then ferment the remaining 30 L then rack onto first batch and begin lager phase if desired.

Probably less infection risk this way too

That’s not really blending though, blending is mixing 2 (or more) different beers to create a third beer.

That is just fermenting the same batch consecutively in separate fermenters and mixing it back together at the end. It would carry more infection risk than fermenting it all together.

Having said that OP is fermenting 45L in a 50L keg which can be done but is a bit tight on head space.

 

[MHB]

Probably get away with 5L of head space if you used a good antifoam, there are a few on the market.
Have played with antifoam in a heff that trying to escape, worked well.
Mark

 

[Benn]

Beersmith Podcast #128 (39mins)
John Palmer talks about yeast.
Quite relevant to what you're proposing DB

My initial thought is that yeast can't go on multiplying (dividing themselves) over and over despite addition of fresh wort, about 3-4 splits and they've depleted their initial reserve of 'nutrients' and should be entering the stationary phase and settling out rather than being force fed sugars from additional wort pitches (a bit like under pitching)
I'm sure someone far more learned will weigh in soon with the science.
Cheers

Attached a link to the iTunes/podcast just in case you're running Apple:
https://itunes.apple.com/au/podcast...wing-podcast/id398500515?mt=2&i=1000371470525

 

[S.E]

Probably get away with 5L of head space if you used a good antifoam, there are a few on the market.
Have played with antifoam in a heff that trying to escape, worked well.
Mark

Yep just thought I’d point out the tight head space.

Just been down to the garage to check on the 61L I have fermenting with about 8L head space its foaming out the blow off but not too badly. It’s going to make harvesting the co2 in to a bit messy though so I’d better clean up a fresh blow off tube to use for that when it calms down hopefully this afternoon.

 

[Droopy Brew]

We would have to have a long talk about what you mean by experimentation.
I'm all for exploring possibilities, but in a way that the results are meaningful, repeatable and measurable. Probably why I have so many problems with some of alleged experiments.
Mark

Would you agree that if I did this and turned out a beer that was free of yeast faults such as diacetyl, actelaldehyde etc then it would be a valid conclusion that this method can and does work?
If there were faults then it does not mean it cant work, it would require further experimentation to isolate potential variables.
I can experiment with drugs but doesnt have to be on a scientific or clinical level. As much as I know you are right into the full due process of science I would argue that trial and error is still a form of experimentation.