Seeking advice - I get a lot of pellicles

[Cavpilot2000]

So I'm primarily a beer brewer and I've got that locked down just fine. But I also make a couple ciders a year.
In recent years I've been frustrated as about 50% of them (ciders) end up with pellicles on top in the carboy while conditioning.

My source of juice is a nearby cidery where I get fresh-pressed unpasteurized juice.

Last year I started sulfiting them on pickup and letting that disperse for a day before pitching yeast. The sulfites didn't prevent 2 of 4 from getting pellicles on the surface.

So my questions are as follows:

1: Should i buy pasteurized juice?

2: Is the unpasteurized cider likely the source of the contaminant? Or is it possible poor sanitation in my equipment (buckets for primary and glass carboys for aging/conditioning)?

3: Is the cider a loss if it has pellicle on top? I have always thrown them out even if they tasted okay because I figured it was infected and not likely to get better.

4: If it is a loss once infected, would the pellicle interfere with turning it into vinegar (trying to salvage something out of it)?

I'm just frustrated because it's not like 5 gal of juice plus yeast and my time is cheap, and I hate throwing out half of my batches.

 

[Maylar]

How long into the process does it take for this to happen? And what is your process?

 

[Cavpilot2000]

How long into the process does it take for this to happen? And what is your process?

Typically it shows up about a month after fermentation. Thin white scum on top that gets heavier over time.

Process: It has varied over time, but let's look at last year's 4 batches:
50ppm sulfite initially, leave it open but with cheesecloth over it to let sulfite dissipate for 24 hours.
Pitch yeast and ferment.
After majority of fermentation subsides (90%+ complete), I rack to a carboy for secondary and to get off the sediment.

I let that sit for a few weeks to settle then rack to carboy for aging/conditioning with maybe 1/8 tsp of NaMeta for about 3-6 months. It's usually during this that the scum appears on top, if it is going to.

 

[Maylar]

1/8th teaspoon sulfite for how many gallons? And do you take measures to eliminate head space in the secondary?

 

[Cavpilot2000]

1/8th teaspoon sulfite for how many gallons? And do you take measures to eliminate head space in the secondary?

5 gallons.
I know that's not a lot, but that's just to put it in storage. It's already been sulfited at the beginning.

I do try to eliminate headspace, but sometimes I can't. However, headspace should not account for causing an infection.

 

[Maylar]

The sulfite at the beginning is likely to be gone by the end of primary. Headspace (oxygen) and bacteria can make a pellicle.

 

[RPh_Guy]

1: Should i buy pasteurized juice?

Try different juices that you have available and see which one you like the best.
I've had good success with my local unpasteurized juice, but also good success with unfiltered pasteurized juice (particularly organic).

Pasteurization doesn't necessarily make it better or worse in my opinion.

2: Is the unpasteurized cider likely the source of the contaminant?

Absolutely! By contaminant, you mean the microbes naturally present in the fresh juice.

3: Is the cider a loss if it has pellicle on top? I have always thrown them out even if they tasted okay because I figured it was infected and not likely to get better.

Ugh, no. Some of my best ciders have pellicles. Extremely delicious.

4: If it is a loss once infected, would the pellicle interfere with turning it into vinegar (trying to salvage something out of it)?

A pellicle simply indicates the presence of wild yeast and/or bacteria, just like foam indicates the presence of yeast during a clean fermentation. It's absolutely nothing to be concerned about when you're dealing with unpasteurized juice. Purely cosmetic.

I'm just frustrated because it's not like 5 gal of juice plus yeast and my time is cheap, and I hate throwing out half of my batches.

Please stop dumping them

As @Maylar suggests, pellicle formation can be prevented by protecting from oxygen and maintain proper pH-adjusted sulfite levels (molecular SO2 around 0.6-1ppm).

Or you can allow the wild microbes to work by not adding sulfite, which is certainly a valid option. Over a period of weeks-months it will undergo MLF, reducing the acidity.
Without sulfite, tighter oxygen prevention is required to avoid vinegar production (acetic acid is only produced in the presence of oxygen).

You can even allow the wild microbes to do the entire fermentation.

Cheers

 

[Cavpilot2000]

OKay, thanks guys!
I've tasted the batched with Pellicles and they've tasted fine to me, so it's good to hear that they're not a loss!
I will rest easier.

 

[Cavpilot2000]

As @Maylar suggests, pellicle formation can be prevented by protecting from oxygen and maintain proper pH-adjusted sulfite levels (molecular SO2 around 0.6-1ppm).

Cheers

How do you calculate this?
I use sulfites in brewing ("LODO"), so I am familiar with their use, but not calculating "molecular SO2" levels. Is it the same as just saying x ppm sulfite, or is there a conversion of ppm sulfite to ppm SO2?

 

[RPh_Guy]

How do you calculate this?
I use sulfites in brewing ("LODO"), so I am familiar with their use, but not calculating "molecular SO2" levels. Is it the same as just saying x ppm sulfite, or is there a conversion of ppm sulfite to ppm SO2?

Based on the pH, a small fraction of the free sulfite (SO3) is present as molecular SO2. The molecular SO2 portion is responsible for the antimicrobial activity of sulfite.

This has a good sulfite calculator:
http://www.fermcalc.com/FermCalcJS.html

Pre-fermentation use of sulfite is complicated by the fact that much of the sulfite that you add (around 30-70%) is immediately inactivated by various compounds in the must, and there's no way to know how much without actually measuring the free sulfite. So targeting an optimal sulfite level to kill (sterilize) the microbes beforehand without pasteurization can be challenging if not impossible. Likely some will survive.

Proper aeration before pitching will remove any pre-fermentation sulfite that you add. Aeration turns sulfite into sulfate.
If you pitch without aerating (not the best idea), the sulfite/SO2 will off-gas with the massive amount of CO2 released.

Post-fermentation it stands to reason that little or none of the sulfite you add will be inactivated, so the anti-microbial activity is easier to control.... Fortunately this is when tighter control matters most (if you're going for fully clean cider).

...
If you've ever had Shacksbury Dry cider (available in cans), that's pretty close to my ideal cider. There's definitely a noticable amount of wild yeast character in there, although it could be better (mine is, in one of my pilot batches attempting to replicate it).

Cheers

 

[AzOr]

This happens to me almost every time I press my own apples. I sulfite juice for 24 hours then pitch yeast. About 3-4 weeks after pitch I get a thin whitish film on top as well. This has never happened to store bought pasteurized juice.

What I have done in past is rack into a keg and add sorbate and sulfites. I backsweeten, carb then pasteurize. I'm pretty sure that pasteurizing will kill any wild beasts. The ciders have turned out great.

 

[Bilsch]

I only use my own apples and have never had this happen but then I do the handling and pressing a bit different. During the season as I collect the apples, from windfall or just selective picking, the fruit gets washed, dried then go into a big chest freezer dedicated to this. When the day comes to squeeze, I thaw the apples and they go in the press whole. The pressing and juicing this way is very easy and as the cider comes off it's quite clear and almost white because there hasn't been any oxygen contact until the skins finally split under the pressure. Dry yeast is added sparingly as the juice runs off into the collection so it gets a head start and quickly mops up any oxygen that makes it's way into the cider. It all goes straight into brewbuckets capped off with airlocks in place until a few points over the terminal gravity and is then close transferred to purged kegs to finish the last few points of sugar. The whole process is very clean and there is little chance for unwanted organisms to get in and get a foothold to cause any weirdness.
Lodo.. it's not just for beer anymore!

 

[AzOr]

I only use my own apples and have never had this happen but then I do the handling and pressing a bit different. During the season as I collect the apples, from windfall or just selective picking, the fruit gets washed, dried then go into a big chest freezer dedicated to this. When the day comes to squeeze, I thaw the apples and they go in the press whole. The pressing and juicing this way is very easy and as the cider comes off it's quite clear and almost white because there hasn't been any oxygen contact until the skins finally split under the pressure. Dry yeast is added sparingly as the juice runs off into the collection so it gets a head start and quickly mops up any oxygen that makes it's way into the cider. It all goes straight into brewbuckets capped off with airlocks in place until a few points over the terminal gravity and is then close transferred to purged kegs to finish the last few points of sugar. The whole process is very clean and there is little chance for unwanted organisms to get in and get a foothold to cause any weirdness.
Lodo.. it's not just for beer anymore!

I like this. How many bushels or pounds can you fit in your chest freezer? I have a chest freezer as well that I use as my Ferm chamber that could be used to freeze apples.

 

[Bilsch]

That's a good question. I never weighed but a full 21.7cu/ft freezer yielded 15 gallons of cider with a few bags of frozen apples leftover that haven't been pressed yet. One of the best parts of doing cider this way is I can be super lazy about getting around to pressing because the apples will wait pretty much indefinitely for me. The absolute best part is the almost water white color of the juice.

 

[RPh_Guy]

The whole process is very clean and there is little chance for unwanted organisms to get in and get a foothold to cause any weirdness.

Just to clarify, your cider does have plenty of wild microbes like every other unpasteurized juice.

Yours doesn't get a pellicle because pellicles only form in the presence of oxygen.

I assume you ferment and store at a low temp and/or use sulfite for aging? That greatly reduces wild character.

Very cool process!

 

[AzOr]

That's a good question. I never weighed but a full 21.7cu/ft freezer yielded 15 gallons of cider with a few bags of frozen apples leftover that haven't been pressed yet. One of the best parts of doing cider this way is I can be super lazy about getting around to pressing because the apples will wait pretty much indefinitely for me. The absolute best part is the almost water white color of the juice.

I'm pondering sourcing a crap load of apples this fall to press. This may be a good way of spreading out the work over a couple of months without stressing about getting it all done in a weekend.

 

[Bilsch]

Just to clarify, your cider does have plenty of wild microbes like every other unpasteurized juice.

Yours doesn't get a pellicle because pellicles only form in the presence of oxygen.

I assume you ferment and store at a low temp and/or use sulfite for aging? That greatly reduces wild character.

Very cool process!

Thanks. Yes it's entirely possible it's all about the oxygen but also the cold temperature storage of the fruit could have a detrimental effect on some of the microbes. I ferment at ~64f and store the finished kegs in a underground room that stays 54-58f year round. No sulfites or anything else except apples and yeast go in this product.

 

[RPh_Guy]

I imagine freezing the fruit has a similar effect as hitting fresh-pressed apples with sulfite -- it knocks down the wild microbe count to some extent but there are still many present.

Anecdotally I've used a frozen yeast packet to make beer and I've had cider freeze solid and continue fermenting when it thawed.
Scientific data I've seen indicate that freezing yeast has a widely variable effect on cell viability. In some cases the viable cell count is completely unaffected.