Apple Juice - unwanted gel forming at bottom of bottles

[Garry Winter]

Firstly, apologies as this is really a question about apple juice rather than cider. Last year after bottling my apple juice I noticed a thick disc at bottom of the bottle which is like a clear gel. It looks unsightly and when poured comes out as a thick blob resulting in me not being able to sell the whole batch. Can someone tell me what this is (pectin?) and what I can do to prevent it happening again this year. Kind regards Garry

 

 

[Claude Jolicoeur]

Looks like a pectic gel. Try a complete depectinisation of the juice (pectinase followed by a racking). You will probably need to make a few tests before finding the formula that works well for you.

[Andrew Lea]

On 19/08/2015 16:03, Garry Winter wrote:
>
> Last year after bottling my apple juice I noticed a thick
> disc at bottom of the bottle which is like a clear gel. It looks
> unsightly and when poured comes out as a thick blob resulting in me not
> being able to sell the whole batch.

Sounds like pectin. How did you make your juice? Was it pretty much like
this, pasteurising with added ascorbic acid??
http://www.ciderworkshop.com/juicepasteurising.html

What apples did you use? Were they very mature?

Andrew

--
near Oxford, UK
Wittenham Hill Cider Portal
www.cider.org.uk

[Garry]

Thanks for the replies.

The apples were Sunset and from memory they were very ripe. Would it also be a factor that I don't feed the trees at all (eg no chemical or organic nutrients added) they are fending for themselves so to speak.

Thanks

Garry

[Garry]

Sorry, meant to add - yes, that's how the juice was made with same if not a bit more ascorbic but with caps on in a Vigo bath pasteuriser.

Regards

Garry

[Andrew Lea]

You will certainly get more soluble pectin from very ripe apples, but I don't think that tree nutrient status is a factor in this. It's more to do with the way that pectin comes out of the cell walls as the fruit matures.

I did ask if you were using the ascorbic acid method for processing, but you haven't said. One merit of using ascorbic acid is that it helps to hold the pectin in suspension and diminishes gel formation. Also, the longer the time interval between pressing and pasteurising the more the pectin will part degrade and lead to gel formation. Shorter is better.

Claude suggested that you might go quite the other way and plan to totally depectinise to get a fully clear juice by adding pectolytic enzymes. This is not generally done by small producers in the UK but it is certainly a possibility you could try.

Finally, we have assumed that the gel is pectin. Have you had anyone look at it under a microscope to be sure that it isn't mould growth? There is a clump forming mould called Byssochlamys fulva which can produce flocculent growths in pasteurised apple juice, and they look like lumps of cotton wool. Could it be this? If so, it indicates poor cap seals so that air has got in. It is usually sporadic and not in every bottle though.

Andrew

Wittenham Hill Cider Portal
www.cider.org.uk

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[Garry]

Thanks Andrew.

Yes, we use the ascorbic method.

I don't think it is mould - it is like a clear gel and not like cotton wool. Also we didn't get it with our other verieties (Lord lambourne and Spartan) and the same capping machine was used.

I am thinking about increasing the dosage of ascorbic (although I thought I had used ample) and pressing before the fruit gets too ripe. I take it this would help. I would rather try to keep to a cloudy juice.
Kind regards

Garry

[Andrew Lea]

Garry,

I think if you are already using the recommended level of ascorbic (500 ppm) then using more will not help. I am not familiar with juice made from Sunset so maybe it is to some extent variety specific? Using fruit that is not overripe should certainly help.

The only other thing that comes to mind is whether you could have excess levels of calcium or aluminium which may form pectate gels? Many years ago I encountered an apple juice pectate gel from a farmhouse producer, that was aluminium based. We needed quite sophisticated chemical analysis to show that. It turned out that his home made grinder had an aluminium housing and this was the most likely source of aluminium contamination. Probably unlikely in your case but I thought I'd just mention it. Or could you have been using calcium sprays for bitter pit close to harvest time?

Andrew

Wittenham Hill Cider Portal
www.cider.org.uk

[skidbro...@tiscali.co.uk]

Hello Garry (and Andrew)
We have had the same thing here when the apple mix has been wrong. At the
time I know that the pH was slightly too high but didn't have any suitable
fruit to blend and since our juice is labelled as "pure" I could hardly add
any malic acid.
The result (post pasteurisation) was a pectin ring/disc that quite readily
detached itself from the base of the bottle and floated about like a cider
vinegar "mother". It will not be broken by shaking and pours into the glass
like something that Dr Quatermass might be interested in.
Since then I have always tried to get the mix of fruit right and watch the
pH. It's the fruit!
Cheers
Guy
Original email:
-----------------
From: Andrew Lea ci...@cider.org.uk
Date: Thu, 20 Aug 2015 19:49:30 +0100
To: cider-w...@googlegroups.com
Subject: Re: [Cider Workshop] Apple Juice - unwanted gel forming at bottom
of bottles

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[Andrew Lea]

Guy,

Interesting. What's your chosen pH threshold for juice?

There are two sorts of pectin gel. The low pH pectin only type (think jams and jellies), and the higher pH alkali metal type. Typically calcium is the metal. I suspect most of what we see in ciders and juices is this latter type. As the pH rises, the pectin becomes more ionised (negatively charged) and it can more readily gel with whatever calcium (positively charged) is around. Positively charged juice protein can also play a role.

As fruit matures in store, acid is lost by respiration so the pH rises anyway. More pectin leaches out of cell walls due to cell wall softening and protein synthesis also increases. A triple whammy really ;-)

Andrew

Wittenham Hill Cider Portal
www.cider.org.uk

[skidbro...@tiscali.co.uk]

Andrew

Absolute limit: 3.8 but routinely between 3.4 and 3.8. Above pH 3.8 there is a risk of the pasteurisation failing but more important is the mould issue. The pasteurisation will kill any bacteria or live mould that slips through the rigorous hand selection. However, it is ineffectual against mould spores which develop to produce a harmless (see Copella research study) but unsightly white mould on the surface of the product. This has only happened to "St. Botolph's pure apple juice" when the pH has also been too high.

It might be coincidence but it is an absolute correlation.

The big problem with the mould spores is that you will only get two or three bottles in a thousand that get a spore so it is only months later when they are in the pubs or shops that it develops. Still. I haven't had any for a couple of years now.

University of Lincoln use and recommend the use of chlorine in the water bath before the auger but the product that they pointed me to was designed as an industrial cleaner/steriliser and I didn't like the look of it and it has proved unnecessary anyway. 

Best wishes

Guy

[Wes Cherry]

The local fresh juice operations around here spray their fruit with Peroxyacetic acid before it goes to the grinder 

It is fairly effective against mold spores if you can keep the temperature up:

http://www.envirotech.com/pdf/PAA-Efficacy-Time-Temp.pdf

The PAA breakdown products (acetic acid and hydrogen peroxide) shouldn't taint your juice like chlorine could.  You may get more oxidation of the poly phenols from the hydrogen peroxide.   Ascorbic might reverse that.  

-'//es Cherry

Dragon's Head Cider

Vashon Island, Wa US

www.dragonsheadcider.com

To post to this group, send email to cider-w...@googlegroups.com.

[Garry]

Guy - you've described it spot on. Sounds like I am going to have to use it for blending rather than a single variety.

Thanks to all for the advice.

Regards

Garry

[Alexander Peckham]

Andrew,

Your mention of Byssochlamys fulva is very interesting.

We have had chronic issues relating to the development of stringing mass formation in pasteurised bladders of apple juice - like clumps of tissue.  I know that this is also an issue in some commercially available juices locally.  I add 500ppm Ascorbic and hot fill into bladders at about 76C.

I had thought that this was a manifestation of pectin - in part because depectinisation and clarifiction of the juice seems to eliminate the issue.

However, clarified juice just doesn't taste as good to me and I have been looking for a way of creating a cloudy but stable apple juice.

Do you have any advice on how this issue might be managed.

Many thanks,

Alex

[Andrew Lea]

Alex,

I think it's very important that the stringy mass is properly identified. You need to look at it under a microscope, preferably in the company of a beverage microbiologist who is familiar with such things, to ascertain if it is pectin or fungal hyphae and conidia.  It's not safe to rely on an ID by the naked eye alone. 

Andrew

Wittenham Hill Cider Portal
www.cider.org.uk

--

[Andrew Lea]

In the meantime what do you mean by filling into "bladders"? That term is unfamiliar to me. Are they the same as "bag in box" in the UK or "cask" in Australia? Or is it some other form of packaging entirely?

If your problem does turn out to be mould related, then it's important to realise that air is needed for the spores to germinate. Bag in box systems are somewhat air permeable both through the bag itself and also around the tap. That's what limits their shelf life. It is likely that there would be enough air creeping into the bag for mould spores to be germinated if present. In that case I'm not sure what you could do except perhaps pretreat the fruit before pressing with PAA as as Wes suggested. But to make it truly effective you would also have to sterilise the mill and press too. And that wouldn't eliminate any mould hyphae which are already growing inside the fruit. 

So if this a serious problem you might need to go back to bottles. 

Andrew

Wittenham Hill Cider Portal
www.cider.org.uk

[Alexander Peckham]

Thank you Andrew,  

By bladder, I mean the bag in BiB.  We use very low permeability, multi layered, bags and a purpose made plug (as opposed to a tap).  I have kept juice in these for two years and it has stayed good - although colour does show some signs of oxidation. 

I will have to look to see whether I have any of old bags that were affected in the store and get one tested if I do have one.    I now clarify the juice, which I don't really want to do, but this seems to eliminate the issue.

Alex