Open Fermentation

[Ghostie]

Ok, ok, open fermentation has probably been discussed before on numerous occasions in these forums however I just want to share my latest experiment with open fermentation.

After experiencing three 'banana challenged' i.e. no banana flavour to be found brews that I had done I decided to research what I may be possibly doing wrong with the brew. With many varied and interesting internet searches I fell upon open fermentation and the positive affects it has on a beer's flavour enhancements.

So.....I looked up food grade containers and purchased a steel food vessel, brewed a hefeweizen and plonked the wort into the uncovered vessel.

I pitched the yeast four hours ago and will update you on the next four days fermentation (unless it gets an infection then you will never hear from this thread again).

 

[MHB]

I don't know what it is with home brewers, there is another thread running on Pressure Fermentation, there is plenty written on the supposed benefits of both.
In a commercial environment an open fermenter is usually in a room with several other fermenters and the whole room is kept very clean and sterile, its more like a fermenter with a large amount of head space than a fermenter sitting in the great outdoors.
This type of system evolved to prevent infection, which is going to be your largest concern.
Personally I'm happy to ferment in a fridge with the miniscule overpressure that an airlock provides and find infections and fermentation issues pretty few and far between.
Mark

 

[The Mack]

Maybe even a bit of cling wrap sitting over the top with two sides taped down, will still achieve "open fermentation" but also just maybe stop unwanteds floating in..

 

[Barge]

Probably better off playing around with yeast type, pitching rate, fermentation temp etc... but best of luck. Hopefully it works out

 

[JDW81]

I pitched the yeast four hours ago and will update you on the next four days fermentation (unless it gets an infection then you will never hear from this thread again).

I'd wager you'll have an infection in about 48 hours (possible less). All manner of flying/floating/crawling bugs (let alone airborne bacteria/yeast) will have free access to your wort and will have a great time.

Even if it works the first time, the infection rate moving forward will be high.

I'll stick to my usual closed fermentation method, which has served me without infection or issue for a decade.

If you're after more banana flavour then look at adjusting your mash schedule/changing how you handle your yeast/using a different yeast is going to be far more reproducible and reliable than having your wort sit in the open for days.

JD

 

[wide eyed and legless]

Ok, ok, open fermentation has probably been discussed before on numerous occasions in these forums however I just want to share my latest experiment with open fermentation.

After experiencing three 'banana challenged' i.e. no banana flavour to be found brews that I had done I decided to research what I may be possibly doing wrong with the brew. With many varied and interesting internet searches I fell upon open fermentation and the positive affects it has on a beer's flavour enhancements.

So.....I looked up food grade containers and purchased a steel food vessel, brewed a hefeweizen and plonked the wort into the uncovered vessel.

I pitched the yeast four hours ago and will update you on the next four days fermentation (unless it gets an infection then you will never hear from this thread again).

I would be taking the advice proffered by The Mack, cover with cling film. When fermentation is underway then open up and see what happens.
I wanted to visit this one when I was in the Czech Republic last year but it had closed, not the most sanitary looking fermenting room but seemed to work.
http://allaboutbeer.com/secrets-czech-brewing/

 

[Schikitar]

I've never quite understood open fermentation, isn't oxygen the enemy of beer!? So many contradictions in this field..

 

[wide eyed and legless]

I've never quite understood open fermentation, isn't oxygen the enemy of beer!? So many contradictions in this field..

Not really, do you aerate or oxygenate your wort prior to pitching? Open fermenters can use the oxygen it needs in an open fermenter, once the pitched yeast starts to work then there is little chance of anything else getting in bacteria wise and the fermenting wort goes into a secondary when fermentation is about done. I hope Ghostie's trial goes well.

 

[Ghostie]

Thanks for all your thoughts which I will agree are all valid. I pitched my yeast at 8.00am on Sunday morning and when I went to bed at 9.30pm there was little if any obvious activity. Sunday and today have been cold for Melbourne in December and that probably has not helped however on Monday at 5pm I have a nice cover of very thin kraussen.

My open fermenter is sitting in the middle of my storage/garage space where I keep all my brewing stuff. It is not a sterile space but it is also not a very much used space and has little air flow/ventilation.

Last month I had a burnt Guton bottom which you guys gave me good advice on how to clean. This was after a hefeweizen and on brewing this hefeweizen I lowered my watts when boiling from 2500 to 2200....it worked...no burning on bottom.

So.....I've got 15 hours to beat JDW81's prediction that my wort will get an infection (8.00am Tuesday Melbourne time) and thanks to Wide Eyed and Legless for hoping for the best with this fermentation.

PS...I could have used The Mack's advice about the glad wrap before I uncovered the wort.

I've added some pictures as well.

I'll update tomorrow if it still looks good. If not I owe JDW81 a beer......and if it looks good I owe Legless a beer.

 

[Schikitar]

Not really, do you aerate or oxygenate your wort prior to pitching?

I wasn't talking about prior.. give me some credit WEAL! I was more referring to post, but you mention that they transfer just before fermentation completes. So if they end up transferring this to closed fermenters to finish out why not just have it in there in the first place? Is this just a 'cool' factor thing (pun intended) or does it serve an actual purpose?

 

[chthon]

I cover my open fermentation vessel (actually my boil kettle, with trub and all ) with a sterile cheese cloth.

I must say that all my brews with open fermentation (started in July) have been a success. I brewed a WV12/St.-Bernardus Abt clone, a weizenbock, and now a Kasteel Donker. For what it's worth, I don't really notice any off-flavors, I would even say that I find them a bit too clean. Future will tell.

What I do in addition to this open fermentation, it is also because the first part of the fermentation is on the trub, I keep a bit of wort apart, rack the fermented beer after five to seven days to a closed vessel on top of this little bit of wort, and then let the fermentation finish and condition until I bottle.

The main reason for me try it this way was the Brülosophy reason: how to make my brew day a bit shorter.

To let the fermentation start faster, I make sure that I either have an active, attemperated starter, or I hydrate my yeast four hours before I need to pitch (which is also an attemperated started more or less).

 

[MHB]

Couple of things...
Apart from being in a country that produces some of the finest beer in the world
You live in a place with lots of breweries, visit a couple and run you process past them, I think they will all tell you to get your wort of the trub (after they stop laughing at you) and for very good reasons. Do a little research on why we boil a wort and the benefits of trub separation.
Just as a point of interest Belgian breweries invest more in getting as much wort out of the kettle, without trub, than do brewers anywhere else in the world. Mostly its a quirk of Belgian tax law where the excise is calculated on the kettle volume/gravity at the end of the boil. If it didn't matter they wouldn't bother but it does matter.

Brülosophy isn't brewing science, no more than is Mythbusters at best its pseudoscientific entertainment, at worst dangerous if people believe the crap they sprout. There is plenty good information out there go look for some.

When rehydrating yeast 4 hours is too long, anything over half an hour and you are doing more harm than good, better to pitch the yeast as soon as its hydrated or transfer it to a starter (which brings up a whole other conversation).

I did when starting out brewing some decades ago try things like those you are doing, (fermenting in the kettle, ******* with yeast...) and have learned that there are lots of things that affect the finished product, to the point where one of my favourite sayings is "Everything ends up in the glass".
I have also developed a very healthy respect for quality brewing research, it is based on quantifying what works, not just the subjective opinions of, well me/you and our pissed mates. One problem with people like Brülosophy is that when you look at any one small change and say "this isn't all that important" do that enough times and you end up with lots of small changes that add up to a pretty poor beer - crap accumulates.
Mark

 

[goatchop41]

One problem with people like Brülosophy is that when you look at any one small change and say "this isn't all that important" do that enough times and you end up with lots of small changes that add up to a pretty poor beer - crap accumulates.

That's an issue with those who are reading it/interpreting it, not the authors/contributors of the website themselves - people reading the brulosophy stuff think that they can take all of the past 'experiments' and apply them all at once, which is not what the authors/contributors are actually saying. The whole point of the website and their experiments seems to be to show that if you do pretty much everything correctly, you can skimp on one or two things and still make a great beer that is imperceptibly different to one that had everything 'by the book'.

 

[goatchop41]

Personally I'm happy to ferment in a fridge with the miniscule overpressure that an airlock provides and find infections and fermentation issues pretty few and far between

I completely agree. I don't quite understand where the idea that the tiny bit of pressure that an airlock provides will somehow stress out healthy yeast and prevent them from properly fermenting or producing certain desirable flavour compounds. It's just not enough pressure...

 

[djebel]

I completely agree. I don't quite understand where the idea that the tiny bit of pressure that an airlock provides will somehow stress out healthy yeast and prevent them from properly fermenting or producing certain desirable flavour compounds. It's just not enough pressure...

If the airlock generates 1" of head before bubbling (rough guess because I don't have an airlock here to measure), it would put ~0.0361psi on the fermenting wort.

 

[wide eyed and legless]

I wasn't talking about prior.. give me some credit WEAL! I was more referring to post, but you mention that they transfer just before fermentation completes. So if they end up transferring this to closed fermenters to finish out why not just have it in there in the first place? Is this just a 'cool' factor thing (pun intended) or does it serve an actual purpose?

Wasn't having a go at you, but when you oxygenate your wort prior to pitching, how much do you think stays in there? Remember you are putting oxygen into a liquid which is dense and will be forcing oxygen
out. Years ago all home brewers would have been using open fermentation as there wasn't the equipment around then as there is now. Once the wort starts to ferment a shield of co2 and krausen prevents oxygen getting in. When the fermentation is finished then put it into a closed secondary, what are the benefits? Dry hopping will be easier for a start, harvesting a healthy yeast with less chance of it mutating as the pressurised fermentation's can cause it do. Is it cool or hip? I would say your pressurised fermentation's sit in that category, lots of home brewers do a sort of open fermentation, as you may have done just using cling wrap over the top of a plastic drum.

 

[MHB]

Given P=Ro*g*h (density, gravity and head in meters to get kPa)
The water in the airlock has a density of 1, g is a given (9.81) and head say 25mm or 0.025
P (kPa) = 1*9.81*0.025 = 0.245kPa (close enough to the PSI given above)

Just enough pressure to keep any gas flowing out and to stop anything getting in. Certainly not enough to cause any problems to the yeast but enough to reduce the chance of infection appreciably.

Got no problem with open fermentation just think that under the conditions most home brewers work under, its going to cause problems with infection control, without any benefits in terms of flavour.
Mark

 

[malt and barley blues]

I remember when the stone ware bread crocks used to be used as a fermenter covered with a clean tea towel. Nothing else available in those days.

 

[koshari]

I've never quite understood open fermentation, isn't oxygen the enemy of beer!? So many contradictions in this field..

the oxygen doesn’t really affect the open fermentation as you get a layer of co2 on the top of the fermenter.

I went on the Batemans beer tour in Lincolnshire a couple of years back, they open ferment all their beers, i took a wiff of the air on top of the fermenter and nearly passed out with the amount of co2 i inhaled. they have been doing it this way for a long time.

https://www.tripadvisor.com.au/Attr...ainfleet_All_Saints_Lincolnshire_England.html

 

[Ghostie]

48 hours after I pitched the yeast I have scraped the kraussen off the top. Temperature is still on the cool side with Melbourne weather under 20 degs again today. No sign of infection and no bad odours. Indeed there is a very sweet smell of banana coming from the brew.

I'll give it another 24-36 hours and then decide when is the best time to move it into a closed fermenter for conditioning.

The main reason I am trying open fermentation derives from an article that I read suggesting that beer could develop more of the better flavours when yeast is open to oxygen. Surface area also plays a part, hence my choice of fermenter. I do not think that pressure under a closed fermenter is relevant. Now maybe yeast does react differently when under pressure however I agree that in a 21 litre batch the pressure of a closed fermentation is tiny.

My current observation is that I can smell banana type smells being produced from an open fermentation when compared to a closed fermentation (I actually took the lid off a closed hefeweizen fermentation to see if I could detect banana but I could not).

Will this all make any difference to the taste of the finished beer? That is what I want to find out.

 

[koshari]

48 hours after I pitched the yeast I have scraped the kraussen off the top. Temperature is still on the cool side with Melbourne weather under 20 degs again today. No sign of infection and no bad odours. Indeed there is a very sweet smell of banana coming from the brew.

so your fermenting at ambient temperature??? and why scrape the kraussen layer off? has been mentioned that the layer on the top protects the work from oxygen in the air.

 

[Reg Holt]

Good article here by Jim Busch explaining open fermentation and the reason for skimming.
http://www.brewery.org/library/OpenFerm.html

 

[Barge]

Couple of things...
Apart from being in a country that produces some of the finest beer in the world
You live in a place with lots of breweries, visit a couple and run you process past them, I think they will all tell you to get your wort of the trub (after they stop laughing at you) and for very good reasons. Do a little research on why we boil a wort and the benefits of trub separation.
Just as a point of interest Belgian breweries invest more in getting as much wort out of the kettle, without trub, than do brewers anywhere else in the world. Mostly its a quirk of Belgian tax law where the excise is calculated on the kettle volume/gravity at the end of the boil. If it didn't matter they wouldn't bother but it does matter.

Brülosophy isn't brewing science, no more than is Mythbusters at best its pseudoscientific entertainment, at worst dangerous if people believe the crap they sprout. There is plenty good information out there go look for some.

When rehydrating yeast 4 hours is too long, anything over half an hour and you are doing more harm than good, better to pitch the yeast as soon as its hydrated or transfer it to a starter (which brings up a whole other conversation).

I did when starting out brewing some decades ago try things like those you are doing, (fermenting in the kettle, ******* with yeast...) and have learned that there are lots of things that affect the finished product, to the point where one of my favourite sayings is "Everything ends up in the glass".
I have also developed a very healthy respect for quality brewing research, it is based on quantifying what works, not just the subjective opinions of, well me/you and our pissed mates. One problem with people like Brülosophy is that when you look at any one small change and say "this isn't all that important" do that enough times and you end up with lots of small changes that add up to a pretty poor beer - crap accumulates.
Mark

Mark, I have nothing but respect for the knowledge and passion for brewing excellent beer that you bring to this forum. I have been absent for a while now and was happy to see that you are still here championing good evidence-based practice. Furthermore I was hoping you could provide me with a 'recommended reading' list of quality research.

I do wonder, however, how much of the research that I presume applies to large-scale commercial breweries, translates to small-scale homebrewing. For example, beer staling due to oxidation. If a keg is consumed within a few weeks will this be an issue? Probably not. Not trying to excuse poor practice but I can't help but think that some research might be more relevant than others.

We have had discussions about this in the past and I have no illusions of changing your mind on this. Just raising the idea that, if the bulk of research is directed towards brewing large volumes that need to stay stable for relatively long periods of time, there may be a dearth of research applicable to homebrewing.

Happy to be proven wrong here. I am just finding time to get back into brewing and will continue to look for relevant research myself. I would appreciate being pointed towards any books/papers you would consider required reading.

Cheers

Matt

 

[Reg Holt]

This this one on here Barge.
https://aussiehomebrewer.com/thread...for-the-novice-and-experienced-brewers.97940/

 

[MHB]

Barge
Quite agree on the research side of things, research takes funding and the money comes from big breweries and is often spent to solve their problems. We as home brewers really do get hind tit. A lot of the research being done is way to esoteric to be useful to us, but the fundamentals don't change whatever the scale.
Point of fact, most research is conducted on pilot plants, usually these are in the 50-150L range so not too far from where most of us are brewing. Gives a pretty fair indication that what works at a large scale also works at our size.

There is some change in the above, with the rising number of small breweries (particularly in the US) there is a lot more research being focused on the needs of smaller breweries. for example look for anything by Thomas Shellhammer if you are interested in using hops.

Other than that, if you want some really good well researched basic information try the IBD website http://www.ibdlearningzone.org.uk/brewing-exam-resources
Read the stuff by O'Rourke and by Bamforth, I would download all those articles they are PDF's and considering the way the IBD is going I'm surprised they are still free.

There is an O'Rourke on the role of Oxygen, its mainly focused on UK Ale brewing (medium sized plants mostly) and there is nothing in it that I wouldn't take onboard.
I have seen NEIPA go from beer to dishwater virtually overnight, caused by too much O2 pickup during filtering (it was a pretty chunky hop soup that needed filtering) so I think its fair to say that we need to be aware of how much O2 we expose a beer to, its going to be more important in some beers than others. Clearly the more hops the more you need to prevent O2 exposure, to the point where next time I do something that's highly hopped I'll be going totally postal on the whole LoDo thing from start to finish. Wouldn't do that on a Hefei, it simply doesn't matter as much.

So yes, some research will have more importance to us than will other, one point that I think many people fail to recognise is the cumulative impact of cutting lots of corners. It might not matter much if you don't mash at the optimum pH, do a 10 minute shorter mash, a 30 minute boil rather than a 60 or 90 minute boil... But add up all the small effects and you end up a very different beer than intended. In my experience its never a better beer.

Based on a few of decades of brewing and study, I try to make the best beer I can, make every decision on quality rather than quantity or price.
Add it all up and we are talking an hour or two (and hey I enjoy brewing) longer and costing a little more but I believe I get better beer.
The cost of making the best beer I can is really only a fraction of what it would cost to buy an equivalent beer but for the time and money I invest it better be equivalent in quality or its my fault.
Mark

 

[Barge]

Thanks Mark and Reg. Lots of info there to get me started.

Totally agree that focusing on quality over quantity is the way to go. I was guilty of cutting corners to save some money. Happy to say that I know better now.

Anyhow, apologies for the temporary hijack... looking forward to hear more about Ghostie's open fermentation venture.

 

[Ghostie]

so your fermenting at ambient temperature??? and why scrape the kraussen layer off? has been mentioned that the layer on the top protects the work from oxygen in the air.

Ambient temperature is what I am using because my fermentor fridge already has a kolsh fermenting and my fermentor for the open fermentation is too big for the fridge.

I scraped the kraussen off because my research (youtube) showed that it is a good idea to scrape the brown bits (i think this is trub) off and to stir the yeast up a bit for a more effective fermentation.

 

[MHB]

Very 1960-70's thinking on the subject
More modern view is that
1/ there is a very finite amount of "head building" ingredients, skimming takes from that amount.
2/ that skimming "cleansed" the beer, the brown bits are mostly fairly insoluble hop products and that removing them was thought to be a good idea. These days the thinking is that they mostly windup stuck to the sides or being insoluble, in the trub.
3/ It was done to crop yeast, still a valid option in some breweries, removing the early brown foam and cropping from the later heads does yield pretty good quality yeast with little trub. However unless the process is conducted in a very clean environment the amount of infections in the next generation is a real problem.

Open fermentation is really a thing of the past, people with open fermenters may still be using them. But really no one (with a couple of exceptions) is installing new open fermenters. Closed CCV/Unitank type systems have proved to be the best answer in terms of space, fermentation and infection control as well as yeast management...

Mind you skimming off yeast before the ferment is complete also reduces the population doing the fermenting so I cant see how that helps.
Another point is how protective that reported layer of CO2 is, bits of dust carrying bacteria will fall through it, walk past and you will stir it up enough to loose any protection it may be giving.

I know people will keep digging up dated processes and re-discovering them, truth is that a good clean fermenter in a temperature controlled environment will give good results more often than anything else.
Its fun to try new things but don't think its some magic bullet that will make a massive change to your beer.
Look at what bigger brewers are doing and why. The industry standard is temperature controlled closed fermenters operating at or near atmospheric pressure - this is how the best beer in the world is brewed!
Mark

 

[Schikitar]

Open fermentation is really a thing of the past, people with open fermenters may still be using them. But really no one (with a couple of exceptions) is installing new open fermenters. Closed CCV/Unitank type systems have proved to be the best answer in terms of space, fermentation and infection control as well as yeast management...

Yep, this was the part I was having a hard time wrapping my head around -> why anyone would do it, but for existing breweries that have 'always done it this way' and those looking to experiment, no problem! otherwise..

Anyway, I hope you get some interesting results Ghostie, if nothing else you sparked some interesting conversation!

 

[Ghostie]

Yep, this was the part I was having a hard time wrapping my head around -> why anyone would do it, but for existing breweries that have 'always done it this way' and those looking to experiment, no problem! otherwise..

Anyway, I hope you get some interesting results Ghostie, if nothing else you sparked some interesting conversation!

Thanks......why would I do this? For fun, because I can, for excitement, for better results than what I have been getting, for getting up in the morning and seeing if my beer is infected, to smell the fermentation, to watch the Kraussen gently rise and fall and move, to work out a plan and see it work out, to hope that I can brew a beer that I really love. To sit down with a previous brew and plan the next one.

I’m still in awe of making beer. I love the sound of bubbling and the smell of brewing.

I’ll post some more photos tomorrow but at the moment all is looking good. Geez I hope it tastes ok.