A good fermentation is necessary for any brew to turn out successful, and sometimes there’s a second stage of fermentation called secondary fermentation.
There are many opinions brewers have on the purposes of secondary fermentation and there are many associated questions that every homebrewer should know. Therefore, I decided to put everything under one roof and make an ultimate guide to secondary fermentation.
As you’ll see secondary fermentation can be an excellent choice for your brew, but there are also myths about secondary that don’t hold water.
What’s secondary fermentation?
Don’t get confused by the “secondary” as there’s only one fermentation that begins in a primary fermenter anything that follows is just the racking from one container to another.
To make things clear, secondary fermentation is a term used for continuing to store brew in a clean container after the brew has fully fermented (or nearly) in a primary. Secondary fermentation is done in the early phase of brewing as one of the purposes is to make the brew better before it’s finally bottled or kegged and distributed.
We all agree that primary fermentation is a must and can’t be skipped, but how about secondary?
Is secondary fermentation necessary?
Secondary fermentation is not necessary and is an optional method brewers use to complete the brew after primary fermentation. Let me explain in short how different brews benefit from secondary.
Beer
Heavier beer styles with high OG like barley wines and imperial stouts benefit from long conditioning times as such beer style isn’t nearly as good as it can get when it conditions for like 6 months or so. Bulk conditioning comes as a benefit, the bear clears up nicely and it’s possible to tweak the recipe afterward. Lighter beer styles will also benefit from secondary, but you’ll hold them there for a much shorter time. Dry hopping is another popular method for many beer styles and secondary is the right place for it.
Mead/wines
Mead and wines can take a long time to fully ferment and the longer they condition the better they become. For this reason, a secondary fermenter is an excellent place to bulk condition these brews as it sometimes can get over a year before these brews become decent. Although it’s possible to bottle condition, it takes much space and if the brew is not going to be enjoyed soon there’s not much point in bottling. After all, if you ever decide to tweak things like adding new flavors it can be done in secondary but not in a bottle.
Ciders
I find ciders somewhere between beers and mead and wines as they are more similar to meads and wines but do not need such long conditioning times to get good. Ciders will benefit from conditioning but they can be already consumed weeks after the primary. I often find ciders hard to clear up in time as they are quickly consumed in my habitat, and holding one in a secondary for the sole purpose of clearing may not be ideal as it could take too long. It’s better to use Whirlfloc tablets if you need them to clarify ASAP, but if you have time you can just wait. Ciders also benefit from later additions you can put in secondary like ginger, star anise, and five-spice.
Benefits of secondary fermentation
Clearing
Clearing benefits every beer except for some hoppy IPAs, wheat, and certain Belgium beers that are supposed to be enjoyed a bit “messy. The clearing is also important for other brews including ciders, mead, and wine as it means the floaties from yeast, protein, or herb and fruit particles are suspended at the bottom.
Lots of floaties and sediment will drop even in the primary if you give it extra time, but for homebrews to truly clarify (especially beers) it’s important to give it a few weeks or apply some other method.
After racking to the secondary, all sediment at the bottom will stay in the primary and there will be no longer a chance that it will somehow get mixed up with the brew. This means you can move and shake the secondary without consequences and after another week or two even more sediment and floaties will drop so when you bottle or keg there will be minimal or non-existent mud.
A clear brew is not only an indicator of purity which is aesthetically pleasing as the brew has a crystal clear appearance, but it also noticeably affects the flavor profile.
Sediment contributes to yeast-like, bready flavor, and if there are other particles like chocolate, vanilla, fruit, or herb particles mixed with the sediment they may additionally bring out the harsh flavors you don’t want.
Bulk conditioning
Bulk conditioning is useful simply for its simplistic nature as you don’t have to do much. Think of this as with a zip file, you can store hundreds of files in a folder but not only it will be harder to manage them but they will also take more space.
When compressed, all the files are one and they take up less space on your hardware.
The same is true with bulk conditioning, you leave the brew to condition for a few months in one container free of sediment which could cause autolysis and it takes minimal space after which you keg or bottle it.
Remember, bulk conditioning is suggestable for heavy beer styles, wines, and meads but lighter styles don’t benefit from it as they’ll be amazing even after a couple of weeks of bottle conditioning in the fridge.
You can see what styles benefit from conditioning the most and why to get a clear picture.
Dry flavoring
Sometimes the recipe calls for dry additions such as hops, fruits, herbs, aroma extracts, or anything that fits in. This is done in a fermenter before bottling or kegging and a secondary fermenter is a good choice as you need extra time for everything to mix together.
Dry flavoring is also doable in a primary, but if you have to wait a few more weeks for flavoring why not improve the clarity and reap other rewards of secondary fermentation?
Removing the risk of yeast autolysis
Yeast autolysis is a terrible thing and has happened in the history of brewing causing ruined batches for brewers before they realized how to avoid it. Yeast autolysis is the destruction of cells by yeast’s own enzymes which produces meaty, sulphuric, and savory off-flavors.
Yeast autolysis is caused either when lots of yeast sediment at the bottom is exposed to long-storage times like months after fermentation was complete or to pressure.
This amount of pressure required for yeast autolysis can only occur in large quantities in those big brewery vessels, so a 6-gallon home batch can’t be an issue.
This problem rarely affects homebrewers as we are brewing in smaller quantities and rarely leave brew in primary for a long time, so it shouldn’t worry you but keep in mind that racking to a secondary will certainly remove even the smallest odds of yeast autolysis.
Big breweries fixed this issue by optimizing the time the beer needs to spend in a primary before it’s transferred to another big stainless steel container in which it conditions and is finally bottled. Homebrewers in the past, logically copied everything they could from breweries as the methods that worked for a commercially sold beer must work on homebrewing scale, but sometimes there’s more than what meets the eye.
Easier bottling
If your secondary fermenter has a spigot then it’s also called a bottling bucket and as such it’s worth using it for bottling. Spigot allows for a bottling wand which is ideal for bottling purposes as it minimizes splashing and thus oxidation. You don’t have to remove the lid and use a siphon as all you need to do is open the spigot with an attached bottling wand and viola!
Bottling direct from a primary with a spigot is also possible and I still do it this way, but you’ll always introduce more sediment this way into your bottles.
When should you start secondary fermentation?
Secondary fermentation shouldn’t be hurried as there are no reasons to do so. Any beer, mead, cider, or wine you name it, can stay in the primary fermenter for at least 2 more weeks after the fermentation is complete.
You should rack the brew to a secondary when fermentation is complete in the primary, don’t disturb the yeast before it’s truly done! If the primary takes 7 to 10 days (less or more depending on the yeast) it’s the time after which you rack to secondary.
Moreover, before you decide you’ll rack to a secondary consider whether it’s really necessary for the particular type of brew you are making!
How to know when secondary fermentation is done?
Secondary fermentation is done when you decide it’s done as there are no clear indicators that will mark secondary fermentation as complete.
This all depends on what you want to achieve, if there’s still plenty of sediment and floaties in your brew consider giving it a few more days, if you need to soak the hops, herbs, or spices for 7 days instead of 3 days leave enough time and if you are using a secondary fermenter for conditioning, the secondary fermentation may last for months.
The brew should be already done in the primary, you are using secondary to improve a recipe or quality.
What type of container is best for secondary fermentation?
In secondary, you can clarify, dry hop, condition for, and bottle all from a single container, so I recommend that you use any food-safety fermenter with a spigot.
Although it’s useful, your primary doesn’t have to have a spigot, if you have a bottling bucket with a spigot, so why not use a bottling bucket as a secondary?
Some people find a spigot on fermenters risky as they experienced leaks or infection, so they only prefer a spigot on a bottling bucket.
However, I haven’t ever had an infection or a leak because I use quality equipment (not special nor expensive, just regular stuff), I assure the wheel that compresses the spigot to the container and creates a seal is fully screwed and I always disassemble the spigot and clean it before putting it all back together and using it for fermentation.
With proper sanitation and care, every fermenter can also be a bottling bucket!
Does secondary fermentation need an airlock?
An airlock is needed during secondary fermentation because it’s important to reduce the contact the brew has with oxygen as it could spoil it.
We could even conclude that airlock is more important in secondary fermentation than it is during the primary. This may sound weird, but while it’s possible to ferment without airlock with the open fermentation method, it’s not possible in secondary fermentation.
Open fermentation means there are no lids nor airlocks on the fermenter as Co2 build-up acts as a membrane between the beer and air. This method works for beers because it’s full of grains which also form krausen which acts as a protective layer but is not ideal for other brews.
During secondary fermentation, no additional Co2 is produced, and with time the Co2 in the fermenter evaporates, so it’s important to have an airlock installed at all times.
Is it necessary to add more yeast during secondary fermentation?
No extra yeast is necessary for secondary fermentation as there’s still live yeast that was pitched in primary fermentation.
Yeast goes dormant when it doesn’t have food to eat, so it will be present in the secondary, and all you have to do to awaken it is to feed it some sugar.
Routinely sugar is added at the bottling stage as the whole purpose of reactivating yeast with sugar is to naturally produce Co2 and trap it in a bottle or a keg with the rest of a brew.
However, if you for any reason want to add extra sugar whether it’s malt extract, corn sugar, honey, or whatever you want to complete the recipe you can do it in the secondary and there will always be enough yeast to do its job, so no more yeast pitching is necessary if you pitched enough during the primary.
Yet, if you killed the yeast somehow then you’ll need to pitch new yeast. (This doesn’t happen unless you intentionally kill it or expose it to high temperatures somehow).
Tips for a successful secondary fermentation
How to increase ABV during secondary
To increase ABV in secondary you must add fermentable sugar as there are no other ways the ABV will increase during secondary.
To increase ABV in secondary you can add corn (dextrose sugar) and granulated sugar, but while they will increase ABV, they won’t add to a flavor which is not ideal. It’s better to use honey as it will nicely increase ABV and also add some complexity, yet the best option for sufficiently increasing ABV is to add more malt. It’s recommended to use extract malt as all you need to do is stir it in water, while malt we use on a brew day first needs to be mashed and stopped from enzymic activity by utilizing heat.
There are more sugars you can use for this purpose and each comes with its flavor profile, so feel free to explore more.
How to add flavors
You can add any fruit, spice, or hops directly into a secondary fermenter using muslin bags, but sometimes this is not an ideal option if there’s a chance the addition may be contaminated. This is the reason why I like to soak any flavor enchanter in vodka for a few days before I add the flavored vodka into a fermenter. It’s important to think about sanitation as at this stage errors can happen if you are not careful.
Vodka has a high ABV and sanitizes your addition, but you can also boil it if it’s the case with some flavors like the one that comes from hops. Bear in mind that boiling fruits, chocolate, vanilla, honey, and similar flavors will kill some aromas and there’s a chance of caramelization.
This topic is too wide for me to explain in this subsection, so I’ll soon write an entire article about it.
Cleaning
The longer you keep the brew in a secondary, the cleaner it will get, and usually, 2 weeks can be enough to fully clean the brew in bulk. However, you can speed up this process by cold crashing your brew as it will hasten the process.
Just bear in mind that if you added extra sugar to increase ABV you should first complete that task as cold crashing will put yeast into a dormant state. The same can be said for dry flavoring as it’s important to give your brew some time for everything to come together before shocking it with cold.
Bottle conditioning vs. secondary fermentation conditioning
What’s the purpose of conditioning in a secondary fermenter if you can do it in a bottle? Well, this is possible at the cost of increased sediment and floaties in a bottle, but once the bottles remain undisturbed for 2 weeks, the brew will naturally clear up. The only drawback is that if you disturb the bottles too much, the sediment may get back into the brew and mud it.
Regarding conditioning, the same processes will occur both in secondary fermentation and in a bottle, so there’s no difference.
And finally, as I mentioned somewhere above in the article, bulk conditioning in a secondary is nice when you want to initially make things easier and save space and time.
Because you have to sooner or later bottle, I like to do it straight after the brew fermentation is complete and the brew has cleared a bit, the conditioning gets done in a bottle and I have a dedicated fridge where I can stuff hundreds of bottles in case I am brewing multiple batches.