Bottle conditioning beer is one of two methods used to carbonate beer, where the carbonation occurs in the bottle; the other is forced carbonation where CO2 gas is administered directly into the beer. Although more time-intensive bottling conditioning is a technique that produces an overall higher-quality beer. If done correctly it provides for a preferred mouthfeel, a better tasting beer with smoother carbonation, exceptional head retention, and increased shelf life.
It is a relatively simple technique that is accomplished by mixing priming sugar with recently fermented beer and transferring it to beer bottles, capping them, and allowing the beer to condition (age) for at least 2 – 3 weeks. In essence, what occurs when beer is bottled conditioned is the sugar reactivates the remaining yeast in suspension causing a secondary fermentation within the bottle to occur which produces the carbon dioxide (CO2) responsible for the beer’s carbonation.
The following are the four main factors involved in successfully bottle conditioning beer…
Four Factors of Bottle Conditioning 
Yeast: When commercial breweries are bottle conditioning they typically add more yeast; however, in the majority of cases for home brewers, this is not required.
After a standard fermentation, when sugar is added to the bottles there is ample yeast still in suspension to carbonate the beer perfectly. The only times you will need to consider adding more yeast is if your fermentation time either in the primary or secondary was unusually lengthy; and although rare, sometimes filtering beer can remove yeast resulting in not enough making it into the bottles. We use the bouncer beer filter and have never run into this problem.
Note: Don’t overthink this, needing to pitch extra yeast is such a rare occurrence that most brewers will never experience it.
Sugar: The next factor or component to successfully carbonating your beer is the sugar you use. If you don’t use enough sugar the carbonation will be lacking and if you use too much you can end up with a gusher (when beer gushes out the top when you open the bottle) or a bottle bomb (where the beer bottle explodes as a result of to much pressure within).
The majority of brewers will use corn sugar (dextrose), however other options are cane sugar, malt extract, and even honey.
To determine how much sugar to use there are numerous online priming sugar calculators you can use and even the nomograph from John Palmer’s book. However, if you are going to stick with using corn sugar and you are striving for the typical carbonation level of 2.25 – 2.5 volumes of carbon dioxide then most brewers will use 3/4 cup or 177 grams in a 5-gallon batch. If you are brewing a different size batch then adjust accordingly using simple math.
Another option and arguably a simpler one is to use carbonation drops. Instead of mixing the sugar and beer in a mixing bucket you simply add the drops to each bottle and fill them with beer. We have found that they provide for excellent carbonation.
Time: When it comes to how long to bottle condition if you are pressed for time it is certainly possible that you can have enough carbonation in the bottle after 1 week. However bottling conditioning usually takes at least 2 weeks to adequately carbonate the beer, and 4 weeks is considered ideal. Most home brewers suffer from being impatient and a strong desire to sample their beer, if you find yourself feeling this way you can try a bottle after 1 week and then every week after and decide from there when you are satisfied with the level of carbonation and taste.
Temperature: Once you have filled your bottles and capped them it is time to place them in a room in your home that can maintain a steady temperature. The general rule of thumb is to keep the bottles at approximately the same temperature you fermented at. Room temperature will work fine. We like to condition ours between 65 – 78℉.
When to Bottle Condition Your Beer
The short answer is after fermentation is complete. Noice brewers struggle with knowing how long to ferment their beer.
In some cases, as a result of being in a rush to drink their beer, they will cut the fermentation time short. This causes a few problems including ending up with a beer that was not given enough time to develop its characteristics resulting in flavors you did not intend for it to have.
The other concern with ending fermentation too soon is it can result in too much yeast still being in suspension which when mixed with sugar and racked into the bottles can produce too much CO2 resulting in bottles exploding.
Our recommendation is to ferment for a min of 10 days.
Equipment Required
Bottles and Caps: You can choose to buy bottles or use leftover commercial beer bottles. We advise people to buy bottles intended for home brewing. The reason for this is they are made to withstand the pressure created during bottle conditioning, they are also typically larger so they hold more beer and they are easier to cap.
You can purchase either plastic bottles with simple twist-on caps or glass bottles that have swing caps. If you decide to use commercial bottles then you will also need to pick up a bottle capper and caps.
Bottling Bucket: If you are using carbonation drops you will not need a bucket. However, if you are mixing the beer with the sugar you will need a separate bottling bucket to do so. You can use a fermentation bucket or a more economical option is to just pick up a 5-6 gallon bucket from a hardware store.
Siphon: In order to transfer the beer from the bucket to each of the bottles you will need a siphon. We recommend that you use an auto-siphon with a bottle filler connection. The bottle filler only releases the beer when you press the base of it down on the bottom of the bottle. This makes bottling a much easier and less messy process.
Large Spoon: Lastly you will need a spoon to mix the beer and sugar. The same mash paddle you used during the mash will suffice, as long as you sanitize it.
Steps to Bottle Conditioning Beer
After you have confirmed primary fermentation has finished and you have gathered your equipment the following are the steps you take to bottle your beer…
Step 1: Clean and sanitize your bottles, caps, and equipment.
Wash your equipment and bottles first, a nonscented hand soap works well. Make sure to look inside the bottles if they have any leftover debris. You can either soak them in a solution of bleach and water or use a bottling brush to give them a good scrub.
One way to reduce your workload on bottling day is to immediately rinse the bottles you are going to use after you drink the beer from them.
When it comes to sanitizing we recommend you use a food-grade sanitizer, the industry standard is starsan which is also a no-rinse sanitizer. Soak your bottles and equipment for approximately 10 minutes in the solution.
Step 2: Add the priming sugar.
If you are using the carbonation drops simply place them into each bottle. Follow the instructions on the package to determine how many to use per bottle.
If you are using priming sugar, it is important that it is sterile, it is best to add it to boiling water. The amount of water you use will be double the amount of sugar. Boil the water, add the sugar, and mix it until dissolved, then let it cool to room temperature, and pour it into the bottling bucket. Adding the sugar to the bottling bucket first will help make sure it gets thoroughly mixed with the beer.
Step 3: Rack the beer to your bottling bucket. Using your sterile siphon carefully and without allowing the beer to splash around, transfer it over to the bottling bucket.
Step 4: Gently stir the mixture with your sterile spoon.
Step 5: Fill the bottles.
Using your siphon and bottle filler connection transfer the beer from the bucket to each bottle. Press the bottle filler down on the bottom of the bottle, when you raise it back up the flow of beer will stop. Leave approximately 1” of head space in each bottle.
Step 6: Cap your bottles.
In order to reduce exposure to oxygen if possible, it is best to cap the bottle as soon as you fill it with beer. This is another reason we recommend you use either the plastic bottles or swing top. If you are using commercial bottles that require the use of a capper you will have to cap them when you have finished filling all the bottles.
Once you have finished capping move the bottles to a room temperature space in your home to condition as described previously.
Storing Bottle Conditioned Beer
After you have finished carbonating your beer it is time to store it until you are ready to drink it. At this point you do not have to leave it in a room temperature area, in fact, a cooler space in your home is preferred as it will allow the beer to clear. It is important to always store your bottles standing up and never on their sides. Also, make sure to keep them in a dark space and never in the sunlight. Prior to drinking your beer, it is best to put the bottles in the refrigerator for 24 – 48 hours.
Serving Bottle Conditioned Beer
One of the aspects of bottle-conditioned beer that some people do not enjoy is the leftover yeast residue at the bottom of the bottle. Just like during fermentation when the trub drops to the bottom after the yeast is finished doing its work, the same thing happens in the bottles. This residue will not hurt you and you can drink it. However, it will make the beer appear cloudier.
To avoid this, refrigerate the beer as we discussed, and when pouring go slowly and do not tip the bottle over any further than you need to. It is also advised to not pour the last little bit of beer in the bottle into your glass.
The Final Word
Bottle conditioning beer is a simple process that produces a better carbonation and as a result a superior beer in many regards. Although more time-consuming than kegging it is worth it when it comes to quality. One strategy to have the best of both worlds, i.e. the efficiency of kegging and the quality of bottling is to brew a slightly larger batch than normal, keg 5 gallons of it, and bottle condition the rest, we do this with most of our beers.
P.S. Be sure to check out our offer on the side of the blog or the bottom if you are on your smart device and get access to Robb’s top 5 recipes from his brewpub. Cheers!