Preventing Oxidation AND Natural Carbonation?

So with one 5 gal batch under my belt, I've got a couple of questions. Please forgive me if they're already been asked before!

1. After a while, the batch seemed to take on an odd taste, not like vinegar or anything, just ick. I've been reading into it, and it seems that maybe what I noticed could have been oxidation. Potassium Metabisulphate is supposedly the cure, but I read that it stops fermentation. How can I backsweeten and naturally carb if I use PM? Does the natural carb still work even if PM is added?

I know potassium sorbate stops fermentation, but I'm not clear on whether PM has the same effect as PS. Basically, I'd like to use PM as a preservative, but I still want to be able to backsweeten for natural carb, if that's even possible!

2. I used the plastic bottle test to periodically check the carb level as I was waiting for my batch to carb. According to the bottle test (and I even cracked a real bottle open to try it) the carb level was perfect. However, when I pasteurized, I ended up with about 1/3 of the bottle bursting from the heat (I followed the pasteurization sticky instructions to the T). What did I do wrong? Does how full you fill the bottles make a difference (like I overfilled, maybe)?

I'm on my second batch, and hopefully I can figure out my mistakes this time. Everyone LOVED the first batch (which means I either did a good job or that the cider they'd had in the past was total crap) so I'm planning on doing about 15 gallons this time and a batch of Skeeter Pee. Thanks for the help!!

1. It doesn't stop fermentation. Winemakers use it all the time. Sorbate WILL inhibit re-fermentation, so don't use sorbate. (neither kill yeast, in spite of what seems to be said about these things.)

2. I don't pasteurize, so I'm no help sorry! Some have had good luck with it, but it's not something I've tried (or want to try).

If you've got oxidation, sulfites will help but it won't prevent it totally. I'd look into the process you're using- careful racking, topping up the fermenter when fermentation slows, etc. Good technique will prevent any oxidation.

Potassium Metabisulfite does not stop or prevent fermentation, and can be used as a preservative in cider even when going the natural carbonation route. I use it in every batch, 24 hrs before pitching the yeast, at first racking, and again in the bottling bucket. It's like a miracle ingredient that protects your precious cider from oxidation as well as the common microbial infections.

Sorbate doesn't stop fermentation either, but it can be used to prevent re-fermentation, and works best when used in conjunction with potassium metabisulfite.


Not enough information to help you on your pasteurization problems. How high did you fill the bottles? Using a spring loaded filling wand always seems to leave me with a 'normal' amount od head-space in the neck. Never lost a bottle, though I use 750ml champagne bottles.

Yooper is right. If it's oxidized, it sounds like you might be splashing the cider a little too much when racking or bottling.

How long are your bottles sitting before they start taking on the odd flavor? 6 Months? 1 Year? Is the taste wet cardboard, prunes or cooking sherry? I've had some bottled beers oxidate before, but it took years for them to get that way.

It's possible it's something else entirely. When you describe "ick"...does it smell/taste like old musty leather, cheese, band-aids, bacon?

Brettanomyces is a wild yeast that could be causing a problem. But it's hard to tell from just the "ick" description. I've never had brett in my ciders before but I have seen it in wines. It also added a sort of tart, sour and slightly acidic quality to an otherwise beautiful wine. (along with the above mentioned odors)

I used pasteurized juice, so I don't think natural yeast is a factor. I don't know how to describe the taste. It wasn't undrinkable, but it just seemed off. I think, from the above post, cooking sherry might be a bit close to the description. It was just rough, not as smooth or fresh as it was after the first 3 months. Instead of mellowing and smoothing out with age, it just got a sort of stale taste to it.

I filled the bottles till about 1/2 to 3/4 inch was left. I did a test batch first, only 6 bottles, and those weren't filled quite as high. None of those busted, so I'm thinking that I may have just overfilled. Is there anything else, aside from not splashing too much and using the p. metabisulfate, that I can do to prevent oxidation?

The fill level would definitely have an impact when pasteurizing, atmospheric pressures, expansion & all that. Since KMS (PM as you call it) also functions as an antioxidant/antibacterial it is your best option. Some also choose to add ascorbic acid at bottling, especially if working with apples/pears, due to its antioxidant nature.

Wild yeasts are on everything. No way to get around them. Brewers yeast will usually out perform anything that is in there though. Thats the reasoning for reducing your lag time when you first pitch. It doesn't give the wild stuff a foothold before the (good) yeast takes off.

As everyone else has said, sulfites are probably your best bet for preservation. I usually just drink mine within 2-3 months.

About the bottle bombs:
I'm glad to see you are using the plastic bottle test. I just wanted to make sure of a few things:
1. Make sure you are using a soda bottle and not a water bottles since water bottles are not meant to hold pressure and won't give a very accurate test.
2. Keep an unopened soda bottle around so you can test the carbonation to an already carbonated soda. This is really useful.
3. Make sure the soda bottle has the same volume as your glass bottles (I assume 12mL).
4. make sure that they are being filled the exact same amount (a bottling wand is very useful like someone previously mentioned).

I used to use the sticky bottle pasteurization technique until I continued to have bottle bombs occur almost every time (roughly 1-6 bottles per batch) and it sucked cleaning up glass and a messy stove. I no longer do this. What I do now is a little more forgiving to your bottles and how much CO2 has built up...

I fill my sink with the hottest tap water I can get from the faucet. Then I continue running the water as I load the entire sink with bottles. This allows them to warm up to about 140-145 degrees F. Then I get my pot of water heated up to 170 dergrees NO HIGHER!!! Turn off the heat on the stove (if using electric coil i would even maybe transfer the pot to another burner). Then I simply transfer the bottles to the pot of water and set my timer for 12 min. I added two extra min just to be safe because the pot temp is a bit lower. The most important part is trying to make sure I maintain that 170 and the easiest way to do this is simply to not fill the pot to the max with bottles and have as much 170 water in there without it overflowing after all the bottles have been put in there. Normally the bottles are all submerged under water and I normally only see about a 5 degree temp change from start to the end of the 12 min. When finished take the bottles out of the pot and I put them in a box close to each other. Warm your pot of water back up to 170 and repeat till all the bottles are done. The reason I put them in the box is that glass doesn't like going from extremely hot to cool very quickly and the box allows them to cool slowly. I have had bottles break simply from putting them on the counter after taking them out of the pot (the glass didn't like the cold granite countertop).

I still use this method and have had much better results. I haven't had a bottle start to ferment back up again either.

Something else that helps a lot is when you go to bottle make sure you stir the cider inside your bottling bucket every 10 bottles or so. This helps to ensure that all the yeast is evenly mixed throughout the cider and makes for more consistent carbonation throughout the batch.

Also if you backsweeten try dissolving your sugar or honey in water first before adding it to the bottling bucket (if you use juice or concentrate to backsweeten just make sure it isn't frozen but don't worry about the water). This will also help you get more consistent carbonation throughout the batch.

Hopefully these suggestions help and make sense to you! Sorry this is long... I just wanted to be thorough to help you as much as possible. Having bottled bombs of your amazing homebrew is like a newborn baby dying in front of you.

cjeanean said:

cooking sherry might be a bit close to the description. ...

Click to expand...

That would be a specific description for acetaldehyde.
Acetaldehyde is a natural byproduct of yeast fermentation although it can be exacerbated by certain bacteria (acetobacter) & infection and is the byproduct of the oxidization of ethyl alcohol. In the process acetic acid (vinegar) is created which you may be able to taste.

If you use wine yeast with your cider, there are wine yeasts which resist the problem such as K-1 with high competative factor (aka "killer strains"), and those that create a higher level of sulfites on their own such as EC-1118 which is a high SO2 producer (yup, yeasts actually produce their own sulfites or SO2) which will further inhibit bacteria.
Keeping fermentation temps a bit lower may help too.

In any regard, whatever yeast you are using will actually help clear the acetaldehyde back out.
If this is the fault you've described, next time try keeping your cider on the yeast lees a bit longer and maybe even stirring up the lees a couple times (carefully and without introducing oxygen) to re-suspend it if you are using a high floculation yeast (one that coalesces and falls out of suspension quickly) this should help clear acetaldehyde out if this is in fact the problem. Like I say, one of the actions of yeast is that, through sustained contact and activity, it clears acetaldehyde that may have formed back out, so a good healthy yeast colony ... properly re-hydrated when pitched and fermentation with good conditions helps as well. Other than that, sanitation.

Just a few ideas.

@LandoAllen Pre-warming the bottles is a great idea, thanks for sharing! I had accidentally left some bottles in a water filled pot overnight, and found one of the bottles broken. I'm pretty sure it was a combination of glass stress from instantly heating them and a touch of quick cooling since the basement was around 60 degrees at the time. I'll probably use the box idea and stick them in the oven to cool (oven OFF of course) just to contain any bombs. The bottle that blew up was a cherry cider, making my basement look like a crime scene. I imagine when it happened it was much like the elevator scene in The Shining!