Open Fermentation and/or Different Fermenter Geometry.

[matt76]

I brewed a Düsseldorf Altbier this morning which I'm fermenting open - early days yet but I'm expecting a much bigger krausen than this in the next 24-48hrs

View attachment 102655

Altbier Open Fermentation Update:

I pitched the yeast last Thursday - pixie here was taken this morning (Monday).

It's still got a sticky yeasty krausen on top but not looking like it's dropping yet.

Unfortunately the Tilt battery died yesterday so I don't know the SG - it started at 1.044 and had got down to 1.020. I've thrown in a backup Tilt but the calibration is off so I don't believe what it's telling me, though it has dropped a few more points in the last day.

The forced ferment I'm doing in parallel only got down to 1.015 and the krausen in that did drop. I'm going to leave that going as it's all been less than a week so it might nibble a couple more points.

 

[matt76]

Altbier Open Fermentation Update:

Well for better or worse, it's been 5 days since pitching so I've kegged it. I pre-pressurised it to 5psi just to make sure the lid is seated and fitted a new "Spundy" spunding valve with a pre-set 15psi PRV.

The krausen never fell and I was surprised to find the SG has only gone from 1.044 to 1.019...

Reading around the web it seems like K-97 tends to have, or can have, both these characteristics. I haven't used it much before - first time in a very similar beer it went 1.044 -> 1.015. The next time it went from 1.042 to 1.009 but in that case I re-pitched slurry so maybe it's a pitch rate thing

In any case I think it's a yeast thing and not an open fermentation thing. I'll leave it a few days and see what happens to the pressure gauge and if need be I'll make a small starter of US-05 and throw that in to see if that gets it moving again.

For all that, the hydrometer sample tasted very nice indeed, it didn't taste at all "not done yet" - malty with some berry esters, kind of like a lager meets bitter.

 

[Sadfield]

My experience with K-97 is the krausen is persistent and also a bit gummy looking. It gives excellent foam in the glass.

 

[Twostage]

Altbier Open Fermentation Update:
and fitted a new "Spundy" spunding valve with a pre-set 15psi PRV.

I've got one but not used it yet, which way does the valve work ? clockwise for more pressure or less ?

 

[matt76]

I've got one but not used it yet, which way does the valve work ? clockwise for more pressure or less ?

Dunno - I think there's an arrow on the adjuster at the back but I got some pre-set PRVs (10 & 15psi) you can screw in instead of the adjustable one.

 

[Mr & Mrs Smith]

Altbier Open Fermentation Update:
View attachment 102814
I pitched the yeast last Thursday - pixie here was taken this morning (Monday).

It's still got a sticky yeasty krausen on top but not looking like it's dropping yet.

Unfortunately the Tilt battery died yesterday so I don't know the SG - it started at 1.044 and had got down to 1.020. I've thrown in a backup Tilt but the calibration is off so I don't believe what it's telling me, though it has dropped a few more points in the last day.

The forced ferment I'm doing in parallel only got down to 1.015 and the krausen in that did drop. I'm going to leave that going as it's all been less than a week so it might nibble a couple more points.

The reason I mentioned secondary is my wife does a thing called dropping. That's probably why Twostage mentioned his father doing secondary, single fermenting vessels without any means of rousing the yeast either by pump or stirring would be dropped into another tank. This process roused the yeast and brought the FG down a few more points.
https://zythophile.co.uk/2008/09/24...ry-of-an-almost-vanished-fermentation-system/

 

[Sadfield]

"The beer gets its name partly because it is hopped three times, and also, and more relevantly, because it undergoes, effectively, a triple fermentation, two at the brewery, using what its brewers call the “double drop” system, and one in the bottle."

"The principle of the Dropping System is that the beer undergoes only the main fermentation in the “round” or “square,” and is then dropped down into a second vessel or vessels, in which fermentation and cleansing are completed."

"One of the important processes any brewer has to perform is to remove the excess yeast from his fermenting beer, and Victorian brewers used at least six different methods to achieve this."

The old use of secondary vessels in homebrewing does exactly this.

However, in commercial brewing conical fermenters became popular, but they are just another form of the process, except the yeast is removed and the beer remains in situ. Primary fermentation, remove yeast, secondary fermentation, then transfer to packaging.

This has led to homebrewers, obsessed with speed of grain to glass, to ignoring the second fermentation thinking that using one vessel is one fermentation, resulting in going straight from primary fermentation to packaging at terminal gravity. Often omitting the cleaning maturation phase of the second fermentation. Or, doing it without removing the excess yeast and trub.

 

[matt76]

The reason I mentioned secondary is my wife does a thing called dropping. That's probably why Twostage mentioned his father doing secondary, single fermenting vessels without any means of rousing the yeast either by pump or stirring would be dropped into another tank. This process roused the yeast and brought the FG down a few more points.
https://zythophile.co.uk/2008/09/24...ry-of-an-almost-vanished-fermentation-system/

Thanks, yeah, I think I've seen that article before (still a good read though! )

The whole idea of dropping - even more so than open fermentation - seems totally at odds with brewing today, or at least at odds with homebrewing as I understand it today. Nowadays many of us (I speak for myself here!) are obsessed with eliminating oxygen post-pitching to preserve hop flavour and aroma. So the idea of deliberately introducing oxygen seems somewhat bonkers to me.

(Perhaps it's more of an American practice but for high gravity brews I've heard references to bubbling oxygen through the wort 24-48hrs after pitching - I wonder if that's actually doing a similar thing to dropping??? )

Now, back to my own issues:
- I can't help but wonder if dropping would actually be beneficial with K-97 to help avoid the fermentation stalling/getting stuck as my Google research seems to indicate it can do? (bit late for me this time!)
- Last night I made a small vitality starter with some US-05 in a bid to get my fermentation going again. In preparation to receive this I raised the brew fridge temp from 18 to 20°C.
- This morning the starter is ready to go but bizarrely the pressure gauge on the Spundy has gone from about 2psi to 7psi. I've done some calculations (this is my area of expertise) and a mere 2°C rise can't account for this pressure increase. So either it has stared fermenting again or the pressure gauge is bobbins. Or both!

 

[Sadfield]

I think K-97 would benefit from top cropping or skimming, to remove of some of that dense krausen to allow some greater access to oxygen during primary fermentation.

"A top fermenting ale yeast with low sedimentation characteristics, highly recommended for the production of ales in open fermentation vessels, and for German ales. During fermentation, it will produce a large, firm head."

https://bsgcraftbrewing.com/fermentis-safale-k-97-500-g/

The Internet suggests K-97 is from Uerige, Dusseldorf. They look to use the same sort of self skimming open FV's as the Sierra Nevada ones in my opening post.

 

[matt76]

I think K-97 would benefit from top cropping or skimming, to remove of some of that dense krausen to allow some greater access to oxygen during primary fermentation.

"A top fermenting ale yeast with low sedimentation characteristics, highly recommended for the production of ales in open fermentation vessels, and for German ales. During fermentation, it will produce a large, firm head."

https://bsgcraftbrewing.com/fermentis-safale-k-97-500-g/

The Internet suggests K-97 is from Uerige, Dusseldorf. They look to use the same sort of self skimming open FV's as the Sierra Nevada in my opening post.

View attachment 102882

Ooooh - shiny AND sinister Bond-villain lighting!

 

[Mr & Mrs Smith]

Thanks, yeah, I think I've seen that article before (still a good read though! )

The whole idea of dropping - even more so than open fermentation - seems totally at odds with brewing today, or at least at odds with homebrewing as I understand it today. Nowadays many of us (I speak for myself here!) are obsessed with eliminating oxygen post-pitching to preserve hop flavour and aroma. So the idea of deliberately introducing oxygen seems somewhat bonkers to me.

(Perhaps it's more of an American practice but for high gravity brews I've heard references to bubbling oxygen through the wort 24-48hrs after pitching - I wonder if that's actually doing a similar thing to dropping??? )

Now, back to my own issues:
- I can't help but wonder if dropping would actually be beneficial with K-97 to help avoid the fermentation stalling/getting stuck as my Google research seems to indicate it can do? (bit late for me this time!)
- Last night I made a small vitality starter with some US-05 in a bid to get my fermentation going again. In preparation to receive this I raised the brew fridge temp from 18 to 20°C.
- This morning the starter is ready to go but bizarrely the pressure gauge on the Spundy has gone from about 2psi to 7psi. I've done some calculations (this is my area of expertise) and a mere 2°C rise can't account for this pressure increase. So either it has stared fermenting again or the pressure gauge is bobbins. Or both!

One observation I have made is if a brewing book is written by a professional brewer they invariably mention, racking to a second fermenter, secondary fermentation in a second fermenter both with the intention of rousing the yeast for the full attenuation.
Homebrewers who write books rarely mention using a second fermenter. So maybe it is something they have done in their professional career. I wonder why it is not recommended to carry out a gentle stir, or does that not have the same effect?

 

[MashBag]

Guessing I would say its to do with volumes. Very different processes when you start running hectolitres.

 

[marshbrewer]

I'm at a site for work today and the offices have had a flash new toilet fit out. I was looking at the new stainless steel sink, long (6ft), about 9 inches deep, drain hole, four holes spread across for mounting taps / wort circulation heads......

.....i need help.

 

[MashBag]

... What? Lifting the other end

 

[Twostage]

200mm 1/1 gn 28ltr.

The biggest is 50L. As an aside if one wanted to make a koelship for wild beer brewing, the 2/1 100mm would be good.

View attachment 102557


Any food grade plastic container or storage box is good, cheap way to experiment.

Ordered the 1/1 100mm 13.5 litre one.

My plan is to do a split batch of something and ferment one in this and the other half with in a SS pan with a lid.

Do you want to be on the tasting panel ?

 

[Sadfield]

That'll be interesting. I watch this the other day, that points to fermenter geometry making a difference even with quite similar vessels, without throwing 'open' into the mix.

 

[Twostage]

Ordered the 1/1 100mm 13.5 litre one.

My plan is to do a split batch of something and ferment one in this and the other half with in a SS pan with a lid.

Do you want to be on the tasting panel ?

Got it. I’m assuming that 13.5 ltrs is full to the brim and I should only put 8-9 ltrs in there (unless I’m happy with krausen everywhere ).

 

[MashBag]

That'll be interesting. I watch this the other day, that points to fermenter geometry making a difference even with quite similar vessels, without throwing 'open' into the mix.

Can you trust anyone who calls it 'trooob' & not 'trub'

 

[Sadfield]

Can you trust anyone who calls it 'trooob' & not 'trub'

What? correctly? Yes.

 

[MashBag]

O oh.