A diacetyl rest, where the compound diacetyl is removed can take several days after the initial burst of yeast activity. This is just one example of the conditioning phase of fermentation. The beer needs to be in contact with the yeast for this cleanup to happen, racking the beer off the yeast will leave these undesirable compounds in the beer after bottling.
The other concern about bottling the beer too soon after primary fermentation is that a lot of yeast will still be up in suspension. Every time you pour a beer it will rouse the yeast and you end up with murky, cloudy beer. Waiting for the yeast to flocculate settle out to the bottom of the fermenter avoids this issue. The rate of flocculation depends on the yeast strain, it can take anywhere between days if you have a highly flocculant yeast strain to 1 — 2 weeks for a low flocculant yeast strain.
Taking all of these factors into account how quickly can you bottle or keg from primary fermentation. The problem with leaving a beer in the primary fermenter too long is the yeast. After the yeast have flocculated and cleaned up any of the byproducts created during fermentation they begin to break down. The yeast cells die and this creates unwanted flavours in the beer.
This process is called yeast autolysis. Yeast autolysis creates a kind of marmite or meaty flavour in the beer. In a commercial brewery, the fermentation vessels are much bigger, there is a bigger weight and pressure on the yeast and cells break down quicker.
This is why commercial breweries are quick to remove yeast from the beer after the conditioning is complete. On a home brew scale, there is not so much pressure or heat generated by fermentation to contend with so autolysis happens at a slower rate.
If you do intend to age a beer for a couple of months I would recommend moving the beer to a secondary vessel. High ABV beers for example like Imperial stouts are suited to bulk aging in a fermenter.
Moving it off the bulk of the yeast after weeks would be my recommendation and then leave it for as long as you like in a secondary vessel, several months will be fine.
If you are brewing a straightforward, regular ABV beer though how long is too long? Personally, I have left a beer in primary for around 5 — 6 weeks without noticing any off flavours. I will stick to my 3 weeks as standard operating procedure. If the occasion does arise though there is room for maneuver. I see you talk about big breweries having more pressure acting over the cells would logically break them down earlier. Think of 9 lt for example.
And, would you consider temperature as a critical factor for such time? I quite often brew litre batches and have occasionally left them in primary for a month before. Many thanks for the article — it has reassured me a lot. I typically brew and then 2 weeks later rack the beer as this fits in with my schedule without too many issues! In most situations it is just an unnecessary step. I never, ever secondary and my beer turns out fantastic!!
However, I am contemplating buying a conical fermenter, though they are expensive for what you actually get. Not that I have tons of experience, but my beers come out better after doing a secondary. Plus I like to add my dry hopping at the time of moving. When I started brewing some 12 years ago I would secondary everything, simply because it was highly recommended.
I have recently purchased a couple Brew Buckets from SS Brewtech, they have the conical bottom but no release tap for removal of sediment, however, due to the shape has a lot smaller contact area for the beer and sediment. After reading this article I might test the theory and not rack my Pilsner, however, agree with Jason in regards to big beers, I will probably continue racking my Belgian Ales.
I used to secondary in the early days because I was scared of autolysis in my yeast. So I stopped worrying about it. I kind of forgot about it and went off and did other stuff.
When I came back there was no off flavor that I could detect. For most ales though I leave things on the yeast cake. Then you probably want to bring it back up for bottling purposes. I get crystal clear beer without the use of a secondary. It will mellow faster in bulk than in bottle, and so a few days may cut my wait for optimum drinking down by weeks. But for my session beers? I am firmly in the camp of no, there is no need for a secondary unless the beer is one that requires extended aging barleywines, etc.
If you are dry-hopping, add them to the primary but after the most active portion of fermentation has completed. And, if you are going to lager or age your beer, still do a day primary before racking and give the yeast an appropriate amount of time to complete fermentation and clean up as much of the fermentation by-products acetaldehyde, diacetyl, etc. Autolysis is a greatly exaggerated worry, especially at the homebrew level.
In the end, homebrewers can sometimes be an impatient bunch… and patience is often rewarded well in this hobby! And that leaving your beer in contact with the trub for an extended period can help clean up some of the byproducts of fermentation. Any opinion on this? Is there any science to back this up?
Or do most people add these right into the primary fermenter? I have always gone to a secondary and never had any contamination or oxidation issues. So in fact pro brewers feel that it is beneficial to remove the sediment. If they did not use conical fermenters I would assume that they would use some type of secondary fermenter to separate the beer from the sediment. Your next article should ask professional brewers why they use a conical fermenter and why they choose to remove the beer from the sediment.
Also, most packaged beer, even craft beer, is extremely clear. Even if you cold crash instead of filter you are better off getting rid of the sediment before you cold crash.
I also use to transfer to a secondary but quit about 15 years ago leaving all my beers in the Primary for no more than 2 weeks. Then just hook up a cobra tap after another week or two and the first glass is any left over yeast cake. Just remember to shoot the yeast cake from the keg before you move it! However I do use a secondary to assist in harvesting yeast for the next time. By the way your software works great for small batches. All I did for making my own recipes is adjust the equipment profile and then try to work within the guidelines of a particular style.
I just bought a secondary vessel, but then began to read all these pros and cons. Back in the early days of homebrewing, it was customary for brewers to transfer their beer off of the trub resting at the bottom of the primary fermentation vessel into a secondary vessel for a period of conditioning before packaging. The main purpose of this step was to avoid picking up off-flavors caused by autolysis, or yeast cell death, which can lead to such undesirable characteristics as raw meat or burnt rubber.
This thinking has permeated modern homebrewing. Nowadays, most brewers opt to ferment entirely in a single vessel, with many also choosing to add hops, fruit, wood, and other flavorings directly to primary.
My venture into homebrewing began after the paradigm shift, and while instructions still included recommendations to rack to a secondary, it never was a normal part of my process. However, most of my beers are packaged fairly soon after fermentation is complete, which left me wondering if the amount of time a beer is left to sit in primary has any impact.
To evaluate the differences between beers packaged either immediately after fermentation is complete or after 3 weeks of aging in primary. I started off by collecting the volume of RO water needed for this 11 gallon batch. After adjusting the water to my desired profile, set my electric controller to heat it up then moved on to milling the grain.
With the water adequately heated, I added the grains and stirred to incorporate before checking the mash temperature. The mash was left to rest for 60 minutes, during which I stirred every 15 minutes. When the mash was complete, I collected the sweet wort in my kettle and brought it to a boil. The wort was boiled for 60 minutes, after which it was quickly chilled to slightly warmer than my groundwater temperature.
Using remnant wort from the kettle, I made a couple vitality starters using Imperial Yeast L17 Harvest. The starters were pitched 4 hours later and activity was noted just a few hours later.
Hydrometer measurements taken from each batch at 13 days post-pitch showed both were sitting at the same FG. After another 2 days, I racked one of the beers to a CO2 purged keg while leaving the other in primary for extended aging.
Click pic for Ss Brewtech Brew Bucket review. After 3 weeks, I racked the primary-aged beer to a CO2 purged keg and placed it on gas next to the other beer in my keezer. I allowed both of these beers to lager for 4 weeks before serving them to tasters.
Left: packaged at FG Right: aged in primary. A total of 22 people of varying levels of experience participated in this xBmt. Each participant was served 1 sample of the beer kegged when FG was reached and 2 samples of the extended primary beer in different colored opaque cups then asked to identify the unique sample.
The 13 participants who made the accurate selection on the triangle test were instructed to complete a brief preference survey comparing only the beers that were different. A total of 4 tasters reported preferring the beer packaged immediately after fermentation was complete, 2 said they liked the beer aged in primary for 3 weeks more, 5 had no preference despite noticing a difference, and 2 tasters reported perceiving no difference.
The beers were very similar to my palate, but if I noticed any differences, they were related mostly to the apparent flavors of older, oxidized beer. The idea of leaving beer in the vessel it was fermented in for any amount of time after the completion of fermentation used to be universally condemned by brewers, though these days is considered standard practice for many. For this reason, the practice of racking to a secondary makes practical sense, and the fact tasters in this xBmt were able to tell apart a beer aged in primary for 3 weeks from one packaged when fermentation was complete suggests the extended contact time had a perceptible flavor impact.
My standard approach since I began brewing a few years ago has been to package soon after fermentation is complete, my main impetus admittedly being impatience— the sooner the beer is kegged, the sooner I get to drink it. If you have any thoughts about this xBmt, please do not hesitate to share in the comments section below! All designs are available in various colors and sizes on Amazon! If you enjoy this stuff and feel compelled to support Brulosophy.
Given this reading, I would have liked to have seen closer to 8 weeks to see if participants picked up any undesirable flavors.
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