When preparing to bottle your beer after primary fermentation, most instructions call for adding sugar or corn sugar to kick-off the second fermentation in the bottle and carbonate the beer.

I have seen one instruction however that advises rather to keep about 1.5L of wort before it was pitched in the refrigerator, and simply add this to the beer prior to bottling.

I can't find anywhere a kind of pros/cons analysis to this. What is the best approach?


  • Depending on the beer, you might deliberately want to nuance the flavour by using something other than simple sugar - such as honey or maple syrup perhaps.
    – Mr. Boy
    Commented Sep 17, 2015 at 11:40

5 Answers 5


Using sugar is easier. There is no risk that you have too much gyle or too little. You can just buy extra sugar and be on the safe side. Gyle needs to be saved in sterile containers (I usually fill a few bottles with gyle while it's still boiling hot, which does the trick) and then kept in the fridge. You can just keep the sugar on the shelf.

You can end up with flat beer or bottle bombs either way; make sure to use the right amount of gyle or sugar. Again, sugar is easier here, cause you will need to know the OG of the gyle and the FG of the beer to figure out how much to use. Then again, using 10 to 20% as a rule of thumb may work as well.

That said, when bottling I always use gyle; mostly because the first brewing books I read mentioned only that. Adding sugar to beer still seems weird to me anyway.


Having done both, I can tell you that sugar (corn or table, doesn't matter) is the way to go. It's easy reliable and tasteless. Priming with gyle (the name for what you propose) is uncertain and offers no advantage to your beer.

  • 1
    Using gyle means you can claim to have brewed according to the German Purity Law. It's up to you if this is an advantage to you. Or the beer.
    – Robert
    Commented Sep 15, 2015 at 22:05
  • 1
    I mostly agree, especially that sugar is straightforward and tasteless, but I think it's a bit reductive to say priming with wort offers no advantage. Might it not be more fair to say whatever advantages it may offer probably don't outweigh the complexity of the technique, especially for the average home-brewer? Commented Sep 17, 2015 at 16:00
  • Can you give me an advantage? I've certainly never found one. And from my position, I don't find being Rgebot compliant to be an advantage.
    – Denny Conn
    Commented Sep 17, 2015 at 20:18
  • 1
    Not having to buy sugar (sure it's cheap, but if you can do with what you already have, why not?); using fewer ingredients (I agree the R-gebot is often overblown in its importance, and it's fair that you don't find it to be an 'advantage', but the perception of simple, straightforward beers with fewer ingredients holds sway with many people); it's a link to the past, when brewers had to rely on empirical skill (and probably luck) rather than the ease of sugar (sure, you could say this tradition is bunk too, compared to modern practice, but to me the challenge is part of the fun). Commented Sep 18, 2015 at 4:41
  • 1
    I can hardly imagine that someone wouldn't have sugar on hand, but I guess it's possible. And while your other points are philosophical and may be true for some people, I'm speaking strictly of beer quality.
    – Denny Conn
    Commented Sep 18, 2015 at 15:29

Priming sugar will give you a very controllable, repeatable result with minimal to no impact on flavour, aroma or mouthfeel. Inconsistency when using this method is entirely down to process (i.e. inefficient mixing).

Using Gyle (held wort) is a perfectly acceptable method as well, that will adhere to the German purity law (should that be important to you or your consumer). The risk for flavour alteration is greater, as you are mixing in wort, which hasn't undergone the alterations by yeast, but still contains many flavour compounds and precursors. What is then probably required to mitigate acetaldehyde (green apple) and diacetyl (buttery) flavours is a longer conditioning period before consumption.

A third option for you, is to bottle your still fermenting beer. The residual sugar will still be consumed by the active yeast, and in the sealed bottle build pressure. This can cut time off your typical post-fermentation priming, and still adheres to Reinheitsgebot. This requires a bit closer monitoring of your gravity. The gravity at which you bottle at with residual sugars present will be largely dependent on the final gravity the yeast are likely to reach. Here again, you may want to give the yeast a bit of time to clean up off-flavour causing compounds; but you should be on the same overall timeline for consumption as if you wait and then prime with corn sugar.

Edit: Removed suggested gravity for third method, as it is process dependent and not absolute.

  • 1
    Regarding the last method you mention, there's no specific gravity reading you can bottle at to ensure proper carbonation, because doing it this way is all about bottling with a certain amount of extract left. 1.020 might be perfect for a beer that will finish at 1.008, but not work at all for a beer that would finish at 1.016. The key to the method is knowing (or at least guessing/hoping) where terminal gravity is before the beer in primary gets there (for which a forced-ferment test is key). Commented Sep 17, 2015 at 4:48
  • 1
    Sounds like adding risk for little reward to me!
    – Mr. Boy
    Commented Sep 17, 2015 at 11:39
  • The assumption when pulling from the fermenter that it will reach a certain gravity is the same assumption when dextrose is added post-ferment. One must assume that the yeast are healthy and vital enough to drive the FG down to a given target. I do however, acknowledge that this is strain dependent, and the 1.020 initially cited is arbitrary - will edit post to reflect this. Experimentation and forced fermentation tests are certainly the best way to understand the yeast at hand. Of course repeated brews will help get a better feel for their FG under certain conditions too.
    – John
    Commented Sep 17, 2015 at 21:09

Use sugar, and use a calculator like Northern Brewer's to calculate the proper amount to avoid gushers or bottle bombs.


1.5L is approximately 6 cups. If you're at 10.058 OG this might work. But above that and you could end up with bottle bombs, or under-carbed below that. And this doesn't account for style. Save more than you need, use a calculator, and adjust after OG and FG are known. I use gyle for purely aesthetic reasons, this is a craft hobby and I try to be a much of a scratch brewer as possible. If consistency is what you're after then sugar pills is the only way to go for bottling, as your fermentor volume may vary especially if dry hopping with whole leaf.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.