Mold growth on cider in secondary

[Metalchef1]

I have mold growth on my cider. It's been in secondary for about 4 months? now and I just recently noticed the mold growing on the surface. I slightly surprised to be seeing mold and I'm curious if anyone who has had mold growth can tell me how their final product turned out? I'm simply going to rack from under the mold and continue to age it with less headspace in a glass carboy.

Yes... I know there is a lot of headspace.
Yes... I know it is an oxygen permeable vessel.

Someone was having a sale on cider kits (the cider house select ones). It's just cider not mango, raspberry or any other flavor.

The entire contents with water were boiled and chilled with an immersion chiller... Primary with wlp655 until I hit fg.
The plastic carboy, cap and airlock for secondary were all brand new and oversoaked in an over concentrated solution of starsan.

Obviously... This was an experiment... Using wlp655 with a cider from a kit.. Wasn't expecting much.... As the sugars are 100% fermentable the sacc would do all the work and there would be little or nothing for the Brett, lacto and pedio to actually do.

That being said... I'm still surprised by the mold growth.

Comments please....

 

[RPh_Guy]

It's been in secondary for about 4 months

Waaaaaaay too much headspace for a secondary. Did you at least add sulfite?

Too much oxygen oxidizes the cider, encourages growth of mold, and allows the production of acetic acid (vinegar) by various microbes.

The mold isn't surprising; mold spores are everywhere. There's a reason certain techniques are best practice.

I'm simply going to rack from under the mold and continue to age it with less headspace in a glass carboy.

Please don't.
Mold is allergenic and can produce toxins and carcinogens. It's a health risk.

Cider does have a little bit of unfermentable sugar: Sorbitol.
Also, that's not true about Brett. It does not need fermentable sugars present to contribute flavor.

 

[Metalchef1]

Right.... Too much headspace...i agree... That's why I put it in the original post.....

Regardless of the amount of headspace... And I've had more plenty of times.... Never had mold.... Use the same setup for with plastic and giant headspace for my Belgians so I can have a nice thick pellicle....

Didn't think about any need for sulfite as the entire batch was boiled and the apple "juice" was a thick map packaged syrup..

17yrs...never had mold growth... That's why I'm surprised.


Is there evidence that the entire batch would be ruined from some surface mold? Without lab tests I can't determine what strain of mold it is but does the alcohol content of the product protect it from spoilage in any way? All I know currently is that it smells quite pleasant and not moldy...?

I thought sorbitol was a sugar alcohol? Can sugar alcohols be readily fermented?

"there would be little or nothing for the Brett, lacto and pedio to actually do." I meant that the sacc would do the bulk of the work very rapidly and prevent the other strains from contributing to the final product as much as they would had there been no sacc present in the fermentation.

 

[Metalchef1]

And I welcome acetobacter....

 

[Metalchef1]

Can't find much about sorbitol and fermentation but I did come across an article on tooth decay and apparently strains of lacto can ferment sorbitol so that's interesting...

 

[Metalchef1]

Thanks for the reply RPH....
Definitely interested if you genuinely think there would have been any actual purpose or benefit for sulfite given the supply and process?

And this is a very interesting article about fermentation and mold toxins... Nasty food for thought.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3737493/

 

[RPh_Guy]

Right.... Too much headspace...i agree... That's why I put it in the original post.....

I know, but it's bad practice and it needed to be stated, again. You're always welcome to do it your own way. Doesn't affect me at all

Is there evidence that the entire batch would be ruined from some surface mold? Without lab tests I can't determine what strain of mold it is but does the alcohol content of the product protect it from spoilage in any way? All I know currently is that it smells quite pleasant and not moldy...?

No, there's no "evidence" that that particular mold growing even produces toxins.
Obviously the alcohol isn't a protecting factor.
As I mentioned mold is allergenic to a lot of people and can produce dangerous toxins and carcinogens. They'd be present throughout the cider, not just on the surface.

Some people are deathly allergic to penicillin for example. Certainly plenty of people get cancer (about 1 in 3 actually), moreso those who expose themselves to unnecessary carcinogens. The effect of carcinogens is cumulative.

Ultimately it's your call of course. It would be a complete dick move to serve it to someone else though. Like secondhand smoke, even if you don't care about getting cancer, some of us would prefer to avoid carcinogens whenever reasonably possible.

17yrs...never had mold growth... That's why I'm surprised.

Fair enough, but it's always a risk. Oxygen + humidity + mold spores and there you go.

Didn't think about any need for sulfite

Sulfite is beneficial regardless of the microbes present because it protects against oxidation.
Although, the apple juice concentrate may already be oxidized. I'm not totally sure about that particular product. You could maybe judge by the color how oxidized it is. It looks very dark in the photo but I realize it might just be the lighting.

Wine I've made from FAJC does get oxidized after a while if unprotected by sulfite.

I thought sorbitol was a sugar alcohol? Can sugar alcohols be readily fermented?

It is a sugar alcohol, and no it generally can't be fermented by yeast. That's why I called it unfermentable.

Lactic acid bacteria generally aren't active in cider except to metabolize malic acid to lactic acid (MLF), so they aren't generally problematic. The one large exception is if you stabilize with sorbate; you need sulfite in that case to prevent off-flavor from the bacteria.

"there would be little or nothing for the Brett, lacto and pedio to actually do." I meant that the sacc would do the bulk of the work very rapidly and prevent the other strains from contributing to the final product as much as they would had there been no sacc present in the fermentation.

If there happens to be a Brett contamination, it will certainly contribute flavor in a 4 month period. It definitely does not need sugar.
And it tends to take over the flavor profile.

And this is a very interesting article about fermentation and mold toxins... Nasty food for thought

Yeah, grain does have some small amount of mold toxins. Wort is typically boiled, so the heat may denature the toxins to some extent (I don't know the exact amount). But wild mold growing directly on your beverage is a different story entirely. I'd dump that batch and call it a learning experience.
Sorry about your change in luck.