One of the great ongoing debates that continues to be a topic in the home beer brewing industry is whether secondary fermentation is beneficial to the finished beer and serves any useful purpose, or if it is a complete waste of time and energy.
Many homebrewers who have been crafting their own beers, claim that the risk of contamination and oxidation is greater than the reward of doing a secondary fermentation. Then brewers on the other side of the fence say the risk is totally worth it, because it improves the overall taste and appearance of the beer.
We are here to give you some information about two-stage/secondary fermentation, with reasons why you might want to do it, or why you want to skip it altogether.
What Is Two-Stage Or Secondary Fermentation?
For a much clearer beer and a better overall flavor to the finished product, many beer brewers and the manufacturer of beer ingredient kits usually recommend a two-stage fermentation.
After the primary fermentation phase is complete and the yeast has done most of it’s job by eating and converting the sugars to alcohol, choosing to do a secondary fermentation by transferring the the beer from the primary fermentation bucket, to a second vessel makes a better finished beer.
When you do a secondary fermentation, you are removing the beer from sitting on the yeast cake and sediment that has gathered at the bottom of the fermenter during primary fermentation. This extra step in the beer brewing process is intended to help the beer “age” and become “clearer” as the bits of yeast that are still floating in suspension settles to the bottom of the vessel once again.
Also, by allowing the beer to finish in another fermenter, you are also eliminating the chance of you beer developing unintended and odd flavors from the leftover sediment.
Is Secondary Fermentation Necessary For Homebrew?
If you plan on making a Lager, you most definitely will want to do a secondary fermentation, which is a completly different story and a whole new ball game. But if you are new to homebrewing, making a lager is not really recommended for your first brew, so you will more than likely begin with some sort of an Ale using a beer ingredient kit.
Within the instructions of most of these beer recipes, they tell you that primary fermentaion will usually take between five and seven days, and then have an “optional” step of secondary fermentation, where the beer will hangout for another week to fourteen days. Even though the beer can be bottled directly after primary fermentation, doing a secondary is often recommended for a clearer beer and to prevent “off flavors from beer sitting on used up yeast and sediment.
If you think that you will want to do a secondary fermentation on your first batch of craft beer, or any following batches of beer, you might want to purchase an additional glass carboy, or make sure that the beer brewing kit that you buy already has one included.
Go ahead and check out which beer kits contain a carboy for secondary fermentation on our beer kit review page, if you are looking to buy a starter kit, or planning to upgrade the existing beer kit that you already have.
When To Transfer The Beer From Primary To Secondary
It is recommended that you wait to transfer the beer to a secondary fermenter until primary fermentation has stopped, which should take between five to seven days to finish. It is best to make sure that the gravity of your beer hasn’t changed for a few days by using a sanitized hydrometer to see if fermentation has completed. If you don’t have a hydrometer, you can look and the airlock and see if there is still any bubbling. When you don’t see any bubbling for more than a minute, it is time to rack to your secondary.
So be sure, it won’t hurt to wait a day or two longer to transfer the beer, while waiting for the leftover yeast to clean up any additional byproducts which can add to some undesirable flavors to your beer.
After racking to the secondary, it’s normal that you might see a little bit more activity from CO2 that is being released from the beer being disturbed during the transfer.
How Long Does Secondary Fermentation Take?
Even though it is called secondary fermentation, it is more of a “conditioning” step in the overall beer making process. By the time primary fermentation has finished, most of the yeast has pretty much finished it’s job, and most of the alcohol has already been made. If you choose to do the secondary fermentation, the recommended length of time for secondary can be anywhere from one week to six months.
Beers that have a lower original gravity, like pale ales, will only require a week or two, where the beers that have a higher original gravity, like Stouts, and Barley Wine, can range from four weeks to 6 months.
Just keep in mind, if you end up leaving a lower gravity beer in secondary for a longer period of more than two weeks, you might need to add some fresh yeast for optimal carbonation when it is time to bottle your beer.
Is An Airlock Required During Secondary Fermentation?
Since fermentation is technically finished by time you rack to a second vessel, many homebrewing experts claim that an airlock is not needed. Because fermentation is already complete, there will be no more CO2 buildup, so the choice for many is to use a rubber stopper or a piece of foil to seal the mouth of the carboy.
Even though the rigorous fermenting stage is over and most of the yeast cells are dead, there is still some active yeast that are active and looking for something to eat in your beer. During this time, there is often a small amount of CO2 that is still being produced, which can still build up pressure in the secondary vessel. This is why still using an airlock is probably the right choice, just to be on the safe side.
I have always used an airlock during secondary, not just to keep contaminants out, but also just to let the gases escape if there is a buildup of CO2. Besides, glass carboys are not made to hold large amounts of pressure. and could end up being very dangerous if they explode from too much pressure.
Exposure To Oxygen
One thing that every brewer, whether it’s a commercial brewer in a mega brewery or an amateur homebrewer, is to avoid the introduction of oxygen in their finished beer.
Before fermentation, it is actually good to stir or aerate the wort before pitching the yeast. Oxygen is needed for the yeast to grow while it does it’s work during primary fermentation.
But after the primary vessel is sealed and an airlock is installed, any oxygen that makes contact with the beer from this point on can end up being the cause of many problems with the beer, including spoiling and the shelf-life of your beer.
This is one of the reasons why some homebrewers avoid this step at all cost, and if they do a secondary, they opt to do a “closed transfer” to eliminate the risk of oxygen ruining your malted beverage.
Benefits Of Secondary Fermentation & Why It Is Important
Unless your beer recipe specifically calls for secondary fermentation, it it probably not needed. But even if your recipe does not require it, there are quite a few reasons to do a secondary fermentation anyway.
- Avoiding Off-Flavors In Your Beer: Removing the beer from the primary fermenter which has accumulated a layer of dead yeast and other particles can keep your beer from picking up odd flavors from these sediments that have settled at the bottom of the vessel during the long fermentation phase.
- A Clearer Appearance To The Finished Beer: Many of the beer styles that you will make at home with not have the clarity that you will find in a commercially brewed beer. But if you want the clearest beer possible, racking the beer to a second fermenting bucket or glass carboy, will give more of an opportunity for any remaining trub and yeast that is still in suspension time to settle, will give your beer a much more clear appearance.
- Better Overall Flavor To The Beer: Allowing the beer to sit for another week or two will give the beer more time to mature and “age” which can give the beer better flavor, and better balance.
- Opportunity To Add Additional Flavors To The Beer: During secondary fermentation is where you will most likely want to add any additional flavors like spices and fruits. This is the time where you will also add extra hops to the beer, mainly for the aroma. This is called “dry-hopping”.
Drawbacks Of Secondary Fermentation
As we stated earlier, many beer brewers avoid secondary fermentation unless it is absolutely needed for the type of beer they are brewing. Many advanced brewers really don’t see much of a benefit, and simply isn’t worth the extra time, the risk of infection, and possibly dumping five gallons of once perfectly good beer down the drain.
- Chance Of Infecting The Beer: The most important thing in the beer making process, is to keep everything that comes into contact with the wort, and eventually beer, completely sanitized. Every extra step that is taken during the brewing process, and each time you open the lid of the bucket, you are introducing oxygen, bacteria, and contaminants into the beer, increasing the chance of ruining and infecting your beer.
- It’s An Extra Step: Besides the chance of contamination, many homebrewers want to try their creation as soon a possible and don’t want to wait even longer. If you to enjoy your beer sooner than later, and unless your recipe call for it, you might want to skip the step, which will add another 7 to 14 days before you are ready to bottle.
- More Equipment Is Needed: Ideally you want to use a glass carboy for secondary fermentation instead of a plastic bucket, and many kits do no include the carboy as part of the package. Many first time homebrewers buy the least expensive beer kit that just has the minimal equipment needed to brew a standard batch of beer, so you must buy a glass carboy separately, or a beer kit that has one already included, which will also increase the overall cost of your brewing equipment.
The Pros and Cons Of Secondary Fermentatin
- Can Give More Clarity To The Beer
- Opportunity To Dry Hop & Add Additional Flavors
- Gives An Overall Better Balance To The Beer
- Less Likely To Take On “Off-Flavors” To Finished Beer
- Extra Step In The Brewing Process Requiring More Time
- Risk Of Infecting and Contaminating The Beer
- More Equipment Is Needed: Extra Carboy
- More Overall Cost
Summary & Conclusion
So should you do a secondary fermentation or not? What it all comes down to is what do you want to do? If you are brewing a low-gravity beer, you probably won’t notice much of a difference in the final outcome.
But as a homebrewer, it is definitely something you should learn to do, and become familiar with the process. I personally have done a secondary conditioning phase on more than half of every batch of beer that I have brewed, and not once have I ever had my beer get contaminated or infected.
That doesn’t mean that you will never have infected beer because you don’t do a secondary fermentation at all, and it doesn’t mean you will infect your beer if you do. Yes there are some risks involved every time you introduce oxygen to your beer, but if you follow the directions, and keep all your equipment clean and sanitized, you shouldn’t have any problems.
What it comes down to is your personal preference and what you are comfortable with. If you do that’s great, and if your don’t, that is great too. The only way to know for sure is to both and see what you end up with.
So if you are interested in giving the two-stage fermentation a try, just get an additional glass carboy (new or used) if you don’t have one already, and give it a shot. That will be the only way to see for yourself if it is worth the time and effort or not.