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Headspace in bottles

Discussion in 'General Brewing Techniques' started by DrJez, 12/7/18 at 3:47 AM.

 

  1. DrJez

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    Posted 12/7/18 at 3:47 AM
    Hey all,

    I'm looking at cutting oxidation from certain styles at bottling, hopefully without going to the trouble of gas and bottling wand

    I'm wanting to find out if anyone's tried filling to the top without leaving a headspace? Is this possible? Does it require the same, or less priming sugar?

    I know air can obviously be compressed so this may take some of the co2 charge a priming carb vol calculator would normally estimate, hence carb rates tailored to that(?)

    Thanks!
     
  2. brewgasm

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    Posted 12/7/18 at 5:54 AM
    I doubt you will impact oxidisation by eliminating headspace. I belive that the oxygen in the headspace is consumed rather quickly by the yeast. If you are concerned about o² in the headspace delay crimping the cap for 10 minutes or so. The lid should rattle about as the O² is pushed out by the CO² coming out of solution.
     
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  3. brewgasm

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    Posted 12/7/18 at 5:55 AM
    Also I think that you need the headspace for secondary to work
     
  4. DrJez

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    Posted 12/7/18 at 7:23 AM
    Incorrect. There's far more oxygen within the headspace than yeast can consume
     
  5. brewgasm

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    Posted 12/7/18 at 8:30 AM
    If you have an oxidisation issue it's probably your handling /bottling. Recommended you let the bottles purge for a short time before crimping.
     
  6. MHB

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    Posted 12/7/18 at 11:17 AM
    Head space is absolutely essential!
    If for no other reason than that if you bottle the beer at say 18oC and later it warms up to say 25oC, the beer will expand (and a lot more than glass does) you will either pop the crowns or blow the bottles.
    There are also other reasons, but the big one is to have a volume that can act as a pressure absorber.

    Here is a reply from picobrewery by Carl Townsend (its all in silly system sry)
    How much headspace should I leave when I bottle my beer?

    Back to Ask the Brewmaster.
    Answer: This is a question that seems to have generated a lot of controversy in the past. Some brewers claim that proper carbonation will not occur without some headspace, and will overcarbonate with excess headspace. As it turns out, it is not true; it violates the concept of equilibrium thermodynamics. The Homebrew Digest back in 1996 describes some experiments run by Steve Alexander and Al Korzonas that prove this out. Check out http://hbd.org/hbd/archive/1938.html#1938-17 for example. As long as the beer still has some viable yeast, carbonation depends mainly on the amount of priming sugar, not on the headspace. Bottles with extra headspace will reach full carbonation faster, however. This is because the extra oxygen in the headspace allows the yeast a brief reproductive phase.

    Despite these fairly well run experiments, people expect quite a bit of headspace. This is particularly evident in competitions, where up to 1½ inches is commonly allowed. In part, this may be due to the fact that most of the bottle fillers on the market leave extra room when they are pulled out of the bottle.

    In my opinion, 1½ inches is way too much. Generally, good brewing practice calls for minimizing oxygenation during bottling, so you ought to keep the fill level high. . Any oxygen not consumed by the yeast will go into unwanted oxidation processes. These can degrade the malt flavor, resulting in a cardboard-like flavor, and can degrade hop aroma. The greatest risk in underfilling bottles is the risk of developing acetaldehyde. Acetaldehyde is the result of direct oxidation of ethanol, and has a foul solvent-like aroma and flavor that can make an otherwise good beer undrinkable. Acetaldehyde will invariably form if the fill level is below the shoulder of the bottle. Another risk of underfilling relates to bottle detonation. If the beer is incompletely fermented or overprimed, the bottles are much more prone to dangerous fragmentation.

    If your filler leaves too much headspace, you ought to top it up before capping. Another trick is to leave the caps loose for half an hour or so. As CO2 escapes from the beer it will tend to flush oxygen out.

    So, should you fill the bottle all the way up to the brim? No, since beer expands when allowed to warm up. Expanding beer creates unimaginable pressure (far more than overpriming) that will either break bottles, or at least will cause leakage out of the cap. The amount of expansion will depend on how stable you keep your storage temperature. Don't forget to add a bit for unexpected heat, such as leaving beer in your car, for example. I had one nasty experience where a bottle burst all over the floor of my car. Wow, what a stink!

    I personally fill my bottles quite high. However, I've often gotten comments about high fills in competition even if I've left a half an inch. Thermal expansion requires about 1/8" (1/4" for 22 oz bottles) so I try to keep the fill between ¼" and ½".​

    Given that there is enough yeast to carbonate the beer, there will be plenty to absorb any Oxygen in the head space, as mentioned above.
    Modern bottling wands (the ones with the foot valve at the bottom - I prefer the blue spring loaded ones) will displace just about the right amount of head space, if you fill the bottle to the top, then take out the wand, as brewgasm said a short rest before crimping will reduce the amount of O2.
    Mark
     
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  7. DrJez

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    Posted 12/7/18 at 11:39 AM
    Thanks man, good article. Can't believe I didn't think about expansion!

    I personally think those wands leave too much headspace. It's a little more than a commercial example and about 3-4 times as much as the writeup refers to

    Yeast will not absorb all that oxygen though, there's plenty if evidence available on that topic but as always, also some disagreement
     
  8. MHB

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    Posted 12/7/18 at 12:05 PM
    You are probably right about the bottling wands, but at least you get consistency.
    When you think that he headspace is somewhere in the 15-20mL range and Air is about 20% O2 we are talking (well at 20mL I get ~0.006g ) (unless I ran out of fingers), wouldn't be safe to assume that the headspace was pure air, disturbed beer will gas off CO2 so its going to be lower.. There really is enough yeast to consume the O2.
    Problem is O2 damage can happen in lots of ways and in some cases very quickly.
    Sadly I don't think we can at a home brew level eliminate all O2 pickup at any point in the brewing process (bottling included) but would suggest that there are real benefits to minimising O2 exposure wherever we can through the whole process.
    Mark
     
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  9. DrJez

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    Posted 12/7/18 at 12:48 PM
    Hmmm, interesting science there. Didn't think of that either

    Thanks!
     
  10. citizensnips

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    Posted 12/7/18 at 2:14 PM
    I’d have to disagree and say minimising O2 at a homebrew level to pretty much commercial level can be achieved but takes a lot of know how, some decent equipment and what many homebrewers would look at and say is a pure waste of CO2.

    If you’re concerned with O2 pick up and bottling I recall an experiment brulosophy did with oxidation and aging where a blichman beer gun was used and after having lab tests done, the beer had 25ppm of O2. That said he purged the bottles for 45 seconds prior to filling.
    From memory the experiment went through the different methods of bottling homebrewers used and measured O2 so may be worth your time having a look at their website.

    Also remember bottling is just one area where O2 can be picked up. Don’t make all the effort in the world to get it out of your bottling procedure when you might be transferring into an open keg with an unpurged line.
     
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  11. brewgasm

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    Posted 12/7/18 at 3:23 PM
    Those plastic bottling wands do leave quite a bit of headspace I agree. I have a last straw bottling gun that doesn't leave as much of a headspace. But like I said earlier and as others have also said I think that you would be able to put your mind at ease just sitting the lids on top of the bottles and let the oxygen get pushed out, I know that I said 10 minutes but like Mark quoted 20 minutes should be plenty. And it sounds pretty cool with the lids dancing around like they are little air locks :)
     
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  12. MHB

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    Posted 12/7/18 at 8:53 PM
    If they are getting 25ppm of O2, they are doing lots wrong (no surprise) 25ppb would be a more sensible target.
    Mark
     
  13. gone brewing

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    Posted 12/7/18 at 10:41 PM
    If you're keen to give it a go, it's easy enough to eliminate air in the headspace when bottling with plastic bottles. Just fill the bottle as normal and squeeze the sides a bit before screwing the top on. I did this with just a few bottles over a few batches and couldn't really tell the difference in the beer, except for slightly lower carbonation with the squeezed bottles.
     
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  14. DrJez

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    Posted 12/7/18 at 10:54 PM
    Thanks, I'll be sure to try that!
     
  15. Garfield

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    Posted 13/7/18 at 11:40 AM
    I've used the old gravity fed bottling wand on thousands of bottles (750ml champagne in my case). I fill to the brim, then the head space is only the volume of the wand, as mentioned by other brewers. As for oxidation? Zero. Not once. Never. Not a single beer has shown signs of oxygen exposure.

    The question of "how to avoid oxidation" comes up often. But my question to OP is: do you have a genuine problem with oxidation or is it imaginary? I feel oxygen cops blame for cases where its not an issue. A bit like the ol chestnut "is my batch infected?" when is undergoing a normal/healthy ferment. There's a healthy diligence to take in home brewing, then there's invalid paranoia.

    So what's the fault in your bottled beer you'd like to improve?

    Garf $0.02
     
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  16. citizensnips

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    Posted 13/7/18 at 2:43 PM
    Yep apologies that was ppb.

    Around 26.5 ppb of O2 was averaged out in finished product over multiple attempts on a homebrew setup using the blichman beer gun.

    Looks like it can be done.
     
    Last edited: 13/7/18 at 2:49 PM
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