Why such long primary fermentations?

[stz]

Hello.
Sorry if this is a dumb question, but plenty seem to be doing it so I'm going to assume that people have good reasons for it, but ..

When I started home brewing I left beer in the primary as long as I could be bothered based on my schedule without getting problems. This was usually at least 2 weeks, but often longer. My rational was yeast needs time to complete fermentation and clean up after itself and coming from making wine and mead this seemed short. If I was dry hopping I'd rack to secondary and dry hop for 1 - 2 weeks because this is what everybody was doing, wanting to maximise extract from those expensive hops and it made racking easier because the beer would drop almost bright.

When I started working at a commercial brewery everybody looked at me like I'd come from another planet. Ale gets 72 hours in primary then is chilled for whatever is left of the day and night before transfer to a conditioning tank where it gets whatever is left of the day and night then packaging the following day. The exception is when dry hopping where they go into the fermenter at 72 hours and the chilling is done the following day, means dry hopping is 12-24 hours. We package bright looking beer, but some yeast is still in suspension and secondary fermentation can be considered to continue for another two weeks in cask or bottle before release. This isn't a given though because we also batch carbonate under pressure for kegging and these beers will be chilled down, carbonated and packaged within 48 hours.

Discussion on the topic yielded a bunch of historic attenuation graphs, information on diacetyl absorption, information regarding the length of time to extract all the necessary compounds from dry hopping, discussion about pitch rates and some books to go and read. They have a fair points tbh I can't really fault gravity readings which indicate the beer is done, temperature is controlled pretty well, studies do show the yeast does a fairly good job of consuming the minimal diacetyl produced quite rapidly in the latter stage of fermentation and you can't taste faults in the beer, it wins awards and it has been produced this way for a long time based on industry standard practice.

So why as home brewers are we leaving beer in primary so long? Oxygenation doesn't have to be a problem. Pitch rates can be scaled up to match. Most of us aren't bad at temperature control. Studies show dry hops are breaking down after 12 hours.

The biggest eye opener for me was brewing a big beer (1.082) and seeing it done in three days. This was the kind of beer that I would assume I needed to leave in primary for at least a month.

 

[Sadu]

I'm still yet to understand how commercial brewers get beer out the door so quickly. I think it basically comes down to the fact that fermentor space is money and it's just not viable to have one batch in the fermentor for a month. So they brew the same recipe over and over again and get really good at knowing when the beer is ready and what recipe-specific shortcuts can be taken to speed it along. I'm also pretty sure commercial brewers assume to some degree that bottles will be sitting in someone's warehouse for a few weeks before ending up with the customer.

I have tried the quick lager method over and over, and the beers just aren't as good as ones that have had the proper amount of time. If this was my source of income I would have a greater incentive to figure this out, but for me I just accept that certain beers are going to take a certain amount of time and that's ok.

That said, I took an early sample of my barleywine, came out amazing with about 6 weeks grain to glass.

 

[stz]

We are always adjusting and looking at optimisation, often several variables at once, but pitch approx 836k cells per ml per degree plato for our ales at the moment.

When I first started the brewery was bottom cropping and pitching all of the yeast we had every single time without recording any data, fermentation was rapid, but we had frequent issues with the yeast dropping out of suspension too soon. Not long before that they were using dry yeast which was quite expensive. I performed cell counts using a basic microscope and hemocytometer and used this to estimate viable cells per ml of yeast slurry and scaled up.

We switched to top cropping as well as to avoid selective pressure by cropping the yeast which is bottom fermenting and was quick to drop out of suspension.

We calculated pitching rates for all our main beers from 1.5 million down to 500k per ml per degree plato and started off pitching the high amount, 1.5 million was too quick so we scaled back batch by batch until we hit 836k.

Other things that usually mess up the 72 hour window are inadequate aeration during transfer (we don't oxygenate, but are developing process at the moment) and mash pH. I'm having to work with historic recipes which are not optimised and an attitude of 'well it works at the moment and has won awards so why change it?' which is fair enough. We pitch at 21C and maintain 21C for the first 24h increasing to 23C for the next 48h. We chill gradually to 1C over the next 24h and then transfer to a conditioning tank to hold the beer at 1C for another 24h.

Thing is, you can tell which recipes aren't within the optimum mash pH because the fermentation is all over the place, the quantity and health of any yeast cropped is poor, attenuation is all over the place and you've got specific flavour issues compared to the ones which are good.

But yeah, leaving it in the fermenter longer that 72 hours is never an option due to commercial pressure and production schedules. So many things from home brewing transfer over, but so many do not. The importance of sanitation (while we sanitise everything that touches the beer and are constantly cleaning I think I was more concerned about infection as a home brewer than anyone is commercially) the length of time in primary (anything over 10 days even for home brew seems like lunacy) open topped fermentation vessels (OPEN?!).

That said we've been unable to get lager down below 6 weeks without compromising the flavour so lager gets 6 weeks.

 

[IslandLizard]

You've got a lot of interesting points when comparing a commercial brewery's workflow with the homebrewing one.

A commercial brewery can ferment at slightly higher temps (21C) than homebrewers due to higher pressure (through volume) in the fermentors.

I've brewed a few beers (5.5 gallons batches, 1.074/18.5°P) lately that were surprisingly done or nearly done within 36 hours at 68-70F (20-21C). Fermentation being visible within 4 hours after pitching. I gave them another 36 hours at 72-74F (22-23C) to finish out with little or no difference. I used a Belgian yeast, a good pitch rate from a fresh starter or harvested from a previous but recent batch.

I oxygenated much better, more thoroughly than ever before, so that may have made a difference resulting in much shorter lag times and a healthier, speedier fermentations. Since I wanted more of the yeast's character the slightly higher temps than I normally use (65F/18C) also helped of course.

I'm surprised you don't oxygenate the wort. Are you injecting air and yeast inline during transfer? That may have proven to be sufficient at ca. 6-8 ppm O2, except in those cases where the beer turns out not quite done after 72 hours. Maybe in those the transfer was faster, allowing for less aeration per volume?

Haven't you guys had any trouble with bottle bombs?

 

[Dcpcooks]

I think the home brewer is under pitching or over pitching and and not managing ph at the same levels a pro would. Few if any are cropping yeast and repitching in the time frame a pro would. I suspect that fermentor geometry factors in as well.

It's taken me a while to figure that stuff out and I still have much more to learn. I'm very happy that I can get a beer from grain to glass in 2 weeks for a normal Plato beer.

Thanks for chiming in. I am hesitant to tell home-brewers to push beers through as quickly as a pro would because they don't have the practical experience a pro does. I cook for a living and I can do things faster, better and cheaper than a home cook can because I have the right tools and experience to maximize my skill set for that task. You make something a thousand times and you can rely on experience to guide you and trouble shoot problems as they arise. Like you said above you can manage several changes to a batch simultaneously on the fly because you have that level of skill.

Cheers.

 

[JohnSand]

I think it is a matter of precision.
The pro has the incentive, equipment and knowledge to produce quality beer quickly. The homebrewer has less of all of those things. A homebrewer can replicate professional methods, some here do. The rest of know that with time, our less than professional methods will work.

 

[stz]

I'm surprised you don't oxygenate the wort. Are you injecting air and yeast inline during transfer? That may have proven to be sufficient at ca. 6-8 ppm O2, except in those cases where the beer turns out not quite done after 72 hours. Maybe in those the transfer was faster, allowing for less aeration per volume?

Haven't you guys had any trouble with bottle bombs?

Because we only aerate and do not oxygenate we rely on agitating the wort when filling the fermentors. Our method is to drop it from the top of the fermentation vessels right to the very bottom using an attachment which causes it to fan out in a wide, thin arc exposing it to as great a surface area as possible. There is a balance between maximising surface area and creating huge foam issues which means there is only a narrow range of positions which actually work. It is quite easy to get it slightly wrong and because we are cropping and repitching yeast multiple times the long term health of the yeast is important. You can usually get away with poor aeration once, even twice with a forgiving production schedule, but eventually the yeast cannot do their job.

I was really surprised that we did not oxygenate when I started, especially as aeration alone cannot produce optimal levels of o2 in transfer. The more people I meet in the industry the more I find that oxygenation is actually quite rare and those that do it, have quite a haphazard process for it estimating levels based on volume over time with no real improvement in the beer to show for it. Lots of things can be circumnavigated by the 'almost free' method of pitching more yeast and a lot of what we do is unfortunately based on 'if it anit broke don't mess'. We have access to a lot of yeast compared to home brewing.

Our method under development involves a butchered vortex injector with a 5 micron air stone in line with the transfer alongside a pure o2 cylinder. We don't use it because we don't have an accurate way to measure o2 in the wort so it'd just be pissing in the wind as to process. We haven't currently got problems and we don't want them and there is a list of other more essential improvements already to beg the boss to pay for. As geeks though we wait patiently for the day when the sales team start pestering us to start making imperial IPA's and stouts instead of session pale and hoppy and instead of looking dumb we whip out our process. :rockin:

I think the home brewer is under pitching or over pitching and and not managing ph at the same levels a pro would. Few if any are cropping yeast and repitching in the time frame a pro would. I suspect that fermentor geometry factors in as well.

I cook for a living...

We pitch massively compared to the home brewer. I think that if home brewers made 2-3L starters for each 20L batch then they'd take a day off of their fermentation straight away. As to cropping yeast it never sits more than 3 days before being reused.

Cooking. Oh I see so many similarities between cooking and brewing! We keep ourselves happy and remain passionate hanging on to our work as a creative art form, bringing together exotic ingredients under duress to create something unique with your culinary thumb print stuck in the middle of it and of course it totally is, just one that also involves trying to maximise output, minimise time and cost while getting covered in crap, working as fast as you can for long hours and pretty low pay. Also the boss doesn't care about your creative side, he cares more about how many more people can you serve, how low can we drive the costs of production and can we offer an unrealistic menu which will only cost you the last few minutes of daily sanity you had left. Also he wants to take two hours discussing this when you really should be doing 500 things instead of trying to remain polite listening to his really badly thought out suggestions.

Home brewing is a pure luxury because much like cooking at home you can do your own thing in a relaxed manner. I imagine there is a certain satisfaction in closing up on an evening after twice as many covers as on a typical night seemingly against all odds due to everything going wrong and yet the kitchen handled it like a machine. That satisfaction is nothing like the satisfaction of cooking at home for friends or family, it is knowing that you kicked butt.

 

[stz]

Haven't you guys had any trouble with bottle bombs?

I forgot to say. We package roughly two points off final gravity for cask conditioning and haven't had any problems since carrying out actual final attenuation tests for all products. In the past we've had big problems guessing actual final attenuation from apparent and when using different yeast strains.

Bottling is basically a joke, we hate doing it because we aren't proud of our bottled beers, but nobody has any passion for improving them as it'd be a thankless task while the boss is holding out until we have a proper canning line. We put our priming sugar straight into a conditioning tank flushed with co2, we pump in the beer for bottling and pressurise the tank with co2 from above. We bottle directly off it with a 4 head filler while keeping co2 top pressure on. We have too much yeast in suspension and we have uneven distribution of the sugar leading to wide variation in carbonation, but never bottle bombs.

 

[beernutz]

Hello.
Sorry if this is a dumb question, but plenty seem to be doing it so I'm going to assume that people have good reasons for it, but ..

When I started home brewing I left beer in the primary as long as I could be bothered based on my schedule without getting problems. This was usually at least 2 weeks, but often longer. My rational was yeast needs time to complete fermentation and clean up after itself and coming from making wine and mead this seemed short. If I was dry hopping I'd rack to secondary and dry hop for 1 - 2 weeks because this is what everybody was doing, wanting to maximise extract from those expensive hops and it made racking easier because the beer would drop almost bright.

When I started working at a commercial brewery everybody looked at me like I'd come from another planet. Ale gets 72 hours in primary then is chilled for whatever is left of the day and night before transfer to a conditioning tank where it gets whatever is left of the day and night then packaging the following day. The exception is when dry hopping where they go into the fermenter at 72 hours and the chilling is done the following day, means dry hopping is 12-24 hours. We package bright looking beer, but some yeast is still in suspension and secondary fermentation can be considered to continue for another two weeks in cask or bottle before release. This isn't a given though because we also batch carbonate under pressure for kegging and these beers will be chilled down, carbonated and packaged within 48 hours.

Discussion on the topic yielded a bunch of historic attenuation graphs, information on diacetyl absorption, information regarding the length of time to extract all the necessary compounds from dry hopping, discussion about pitch rates and some books to go and read. They have a fair points tbh I can't really fault gravity readings which indicate the beer is done, temperature is controlled pretty well, studies do show the yeast does a fairly good job of consuming the minimal diacetyl produced quite rapidly in the latter stage of fermentation and you can't taste faults in the beer, it wins awards and it has been produced this way for a long time based on industry standard practice.

So why as home brewers are we leaving beer in primary so long? Oxygenation doesn't have to be a problem. Pitch rates can be scaled up to match. Most of us aren't bad at temperature control. Studies show dry hops are breaking down after 12 hours.

The biggest eye opener for me was brewing a big beer (1.082) and seeing it done in three days. This was the kind of beer that I would assume I needed to leave in primary for at least a month.

What size brewery do you work at?

 

[stz]

What size brewery do you work at?

Typically quote batch size in order to give brewery size which is 20BBL / 3,280L, but fermentation capacity, conditioning and number of brew days change how much beer we produce which is 3,120BBL or 5,116,80L a year. In USA speak this is 4,373 US barrels a year or 1,355,73 US gal.

 

[Hwk-I-St8]

I have to say, this is a fascinating read and quite apropos given my thoughts regarding the NEIPA I just brewed. I dry hopped at 72 hours and could have kegged at 5 days.

I plan to get a tilt hydrometer so that I can graph my fermentation. That, coupled with pitch rate data, will help me figure out optimum pitch rates and boil to keg intervals. I have no need to have fast production, but I hate waiting and see no reason to leave beer in a fermenter longer than necessary.

 

[Dcpcooks]

Because we only aerate and do not oxygenate we rely on agitating the wort when filling the fermentors. Our method is to drop it from the top of the fermentation vessels right to the very bottom using an attachment which causes it to fan out in a wide, thin arc exposing it to as great a surface area as possible. There is a balance between maximising surface area and creating huge foam issues which means there is only a narrow range of positions which actually work. It is quite easy to get it slightly wrong and because we are cropping and repitching yeast multiple times the long term health of the yeast is important. You can usually get away with poor aeration once, even twice with a forgiving production schedule, but eventually the yeast cannot do their job.



I was really surprised that we did not oxygenate when I started, especially as aeration alone cannot produce optimal levels of o2 in transfer. The more people I meet in the industry the more I find that oxygenation is actually quite rare and those that do it, have quite a haphazard process for it estimating levels based on volume over time with no real improvement in the beer to show for it. Lots of things can be circumnavigated by the 'almost free' method of pitching more yeast and a lot of what we do is unfortunately based on 'if it anit broke don't mess'. We have access to a lot of yeast compared to home brewing.



Our method under development involves a butchered vortex injector with a 5 micron air stone in line with the transfer alongside a pure o2 cylinder. We don't use it because we don't have an accurate way to measure o2 in the wort so it'd just be pissing in the wind as to process. We haven't currently got problems and we don't want them and there is a list of other more essential improvements already to beg the boss to pay for. As geeks though we wait patiently for the day when the sales team start pestering us to start making imperial IPA's and stouts instead of session pale and hoppy and instead of looking dumb we whip out our process. :rockin:







We pitch massively compared to the home brewer. I think that if home brewers made 2-3L starters for each 20L batch then they'd take a day off of their fermentation straight away. As to cropping yeast it never sits more than 3 days before being reused.



Cooking. Oh I see so many similarities between cooking and brewing! We keep ourselves happy and remain passionate hanging on to our work as a creative art form, bringing together exotic ingredients under duress to create something unique with your culinary thumb print stuck in the middle of it and of course it totally is, just one that also involves trying to maximise output, minimise time and cost while getting covered in crap, working as fast as you can for long hours and pretty low pay. Also the boss doesn't care about your creative side, he cares more about how many more people can you serve, how low can we drive the costs of production and can we offer an unrealistic menu which will only cost you the last few minutes of daily sanity you had left. Also he wants to take two hours discussing this when you really should be doing 500 things instead of trying to remain polite listening to his really badly thought out suggestions.



Home brewing is a pure luxury because much like cooking at home you can do your own thing in a relaxed manner. I imagine there is a certain satisfaction in closing up on an evening after twice as many covers as on a typical night seemingly against all odds due to everything going wrong and yet the kitchen handled it like a machine. That satisfaction is nothing like the satisfaction of cooking at home for friends or family, it is knowing that you kicked butt.

That so funny! You nailed the kitchen piece spot on! Cheers to you. I wanted to be a chef, so once the kids got a little older I went to school, did the grunt work and worked my way up. Then I open a business and was forced to spend time running the business. So now I brew beer at home to fuel my creativity. I work in a relaxed manor to create the beers I enjoy and love to share.

All my friends say open a brewery, you make great beer and great food. People will love it. The reality is I'd just become an accountant who cooks and moves spent grain. Even with that understanding I'm constantly looking for a location that could work as a brew pub!


I've been meaning to get a microscope and begin learning more about yeast health and cell counts. I think you may have just pushed me over the edge on that!

Cheers

 

[Sailingeric]

Good read! I think a big difference for most of us is brewing is hobby and a beer sitting a week or two in the fermentor is not a big deal since often we do it when have the time. Even if brewed a 5 gallon batch and bottled or kegged another batch ever weekend, I would still have way more beer than i know what to do with.

 

[brewcat]

I think it stems from homebrewers not necessarily pitching enough yeast, bottling (have to avoid bottle bombs), not enough storage, and/or maximizing clarity. We also can take a more relaxed approach not having bills to pay.

I've personally started shrinking time in fermenter and conditioning in kegs since I have the extra storage.

It does seem dry hopping times have come down to 5-7 days max.

 

[Weezy]

The vast majority of fermentation is done in three days, for sure, but that last few percent means a lot. That's when the yeast cleanup after themselves. Sending the beer to the Brite so fast and crash cooling it is risking yeast stress off flavors.

Do you guys take gravity readings?

 

[JONNYROTTEN]

I love hearing how the pros do it.
Interesting with the yeast and PH

Question: Why is it your stuck at 6 weeks for a lager.
I'M just getting into lagering and made a fantastic beer at 3 weeks
What is your procedure?
Diacetyl rest?

 

[Staticsouls]

subbed great info

 

[stz]

The vast majority of fermentation is done in three days, for sure, but that last few percent means a lot. That's when the yeast cleanup after themselves. Sending the beer to the Brite so fast and crash cooling it is risking yeast stress off flavors.

Do you guys take gravity readings?

Yes we take gravity readings first and last thing every day of the week. The fermentation timeline is basically our major indicator as to how the yeast is performing and allows us to predict any future trouble. I've got to stress that while we chill prior to transfer to drop most of the yeast and we condition for another day to drop further yeast we are still talking in excess of 1 millions cells per ml at this point and this is intentional. We cask condition no more than 3 points off final gravity, 2 is ideal as any more and the secondary fermentation is too vigorous increasing cell count. The cask conditioning process might as well be considered part of the fermentation as it is very rare that the beer will be consumed within two weeks of packaging. Either way months in primary is not necessary.

 

[stz]

I love hearing how the pros do it.
Interesting with the yeast and PH

Question: Why is it your stuck at 6 weeks for a lager.
I'M just getting into lagering and made a fantastic beer at 3 weeks
What is your procedure?
Diacetyl rest?

It has just always been made this way. I've never really questioned it. I think they've had problems with it in the past. As a rough guess I'd say that the chiller for the lager isn't great and would take a week or two to bring it down to lagering temperature.

 

[homemaltster]

This thread reminds me how lucky we are to be able to brew just as a hobby. We all have such a romantic idea about the pros, but they probably get jealous of those dudes in a garage taking their sweet time home brewing.

I wonder how often home brewers get into commercial brewing and end up really not digging it.

 

[stz]

This thread reminds me how lucky we are to be able to brew just as a hobby. We all have such a romantic idea about the pros, but they probably get jealous of those dudes in a garage taking their sweet time home brewing.

I wonder how often home brewers get into commercial brewing and end up really not digging it.

Most brewers I've met are passionate about both beer and process control. You need to be able to get just as excited by developing processes, improving take off efficiency and work flow as you do the aromas and sensory aspects of beer and ingredients because you will likely do very little recipe development in the beginning or at least get to push many extremes ever unless it is your own brewery and you are sure you can sell what you produce. Home brewers enjoy so much more potential creative freedom.

So sure, I really enjoy enjoy sticking my head into a bale of interesting hops and digging to break them up getting oils and resins all over my arms until they are literally green and sticky, it is great. I'm also just as happy finding a clever place to keep the big spanner which just made brew day easier. After a while the hops just become another job which is taking up time which you need to get claw back and vacuum sealed bales of high alpha hops are sometimes so rock hard I have to tear chunks off with a frigging screwdriver because my grip is tired and failing.

As an industry there is a lot of having to pay your dues when you start working. 90% of the job is cleaning, lifting and carrying under difficult circumstances with extremes of temperature, unpleasant chemicals and time pressure. You kind of want to know that anybody at any level is capable of doing these basic things when the chips are down. Having been through it I'd be wary of working with people who just happen to like beer and think the idea of brewing is cool because they've made great home brew. I'd be worried they'd quit when they have a difficult day leaving thousands of litres of wort in the copper because they haven't had the fight knocked out of them and love for the brewery properly sanctified with the ritualistic thousand hours of scrubbing before you get to touch the mash paddle.

Any idea that brewing is glamorous kind of goes out the window when we start early, get wet constantly (with water if you are lucky) and on any given day can have to move several tonnes of malt (multiple times if the warehouse is being particularly stupid) Relax and spend an hour measuring out yeast and then several more scrubbing drains, floors and cleaning fermentors.

On the plus side other brewers totally get what it is like and are usually very supportive. I've found that they all want you to do well and make better beer and at least at the moment I've access to a great network of passionate people. There is also the palette training and testing and the chance to try some amazing beers, get feedback and debate on a technical level exactly how and why something is the way it is. It is nice to speculate with really talented people as to just how they achieved a certain aspect of an extreme beer. The festivals are really nice though I'm usually exhausted and losing my voice.

Generally though, if the processes are working it doesn't matter if you make beer or lightbulbs. As a job the hours are long, the pay is not great, the work is very physically and mentally demanding and you get covered in crap nearly every day. Also because the industry looks a bit hip compared to making lightbulbs some bosses will try to take advantage of this by paying very low wages and thus ruin peoples passion and enthusiasm. This is a shame, but I imagine many people feel the same way in other jobs.

Also you need to be able to fix things at no cost using no time while managing to dodge trouble for fixing something you shouldn't have touched, failing to fix something you shouldn't have touched or refusing to fix something you shouldn't have touched.