Keeving: dosage of PME and calcium chloride

[Anders Klausen]

Hello everyone, I am a keever:)

And I have been that for 7seasons now. I have read a lot of wonderfull threads in this forum and I know there is no eksact ansvers - just lots of eksperiments and many good advices.

So I will ask shortly:
When you are keeving a juice with low pH, (eg. 3,1) would it then be a good idea, as a thumb-rule, to raise the dossage of enzyme a bit? Some of my keevings make a perfect "chapeu brun" and others don't. When I'm reading accros the threads (and in Andrew Lee's book) I see that with low pH it's difficult to keeve succesfully because the PME is inhibited by the acid. Even though I have done some succesfully keeved batches of pure Belle de Boskoop and Browns Apple I still see the best keevings on the high pH juices. But when I last week wanted to blend my bittersweet Yarlington mill with the bittersharp Browns Apple the pH is still 3,4 and the and the cap is still not forming (just some gel at the bottom). Should I have raised the dossage of PME since I knew about the low pH?

bonus info:
Today I took a juice sample in a test tube of the abowe mentioned juice and dropped some calcium chloride in it, just for fun. The gel formed instantly! And feld to the bottom. So I thought it might help to ad another dosage to the vessel, and so I did, so it now has twice the recomended dosage. (I guess there will a large cap in a few weeks. )

The temperature was about 10C the first 24 hours from when i added the PME (oct. 23) til I added the CaCl2. Since then it's been about 6C. But today it was 15C.

Best regards

Anders Klausen

[Claude Jolicoeur]

Actually, Anders, it is rather the calcium chloride that reacts with the malic acid. Hence with an acidic juice, it may be a good strategy to increase the dosage of calcium chloride.

However, depending on if you are doing this commercially and where you are, some legislations limit the amount of calcium that may be added. For example in France you can't add more than 160 ppm of calcium which is the quantity there is in 450 ppm of calcium chloride.

Claude

[Anders Klausen]

It is allso my experience that extra calcium chloride provides more gel. But   sometimes I end up with a bucket of gel . And sometimes it gets just perfect by following the recomended dossage.

So I'm looking for a rule, and it seems like the pH plays a part allso(not dupprised). The manufactuer of the keeving kit KLERECIDRE is not generous about instructins. It says that you can increase the addition, but nothing about when and when not...

So when the so-called “flocculation” seems abcent or very poor; is it then because the enzyme hasn't sad the time to work or is it because the dose of calcium chloride should be raised?

So that is the good question...

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[Andrew Lea]

Well it is true in theory that some of the calcium added as calcium chloride could form (non ionic but soluble) calcium malate with free malic acid. But I’m not sure if there is any data to show how competitive that reaction is with the formation of the insoluble calcium pectate gel which is the desired outcome. Maybe Claude has some figures?

It has to be said that the effect of lowered pH on keeving is quite complex. As far as the enzyme goes, it will certainly be less active at a lower pH. This is especially true for natural apple PME but is also the case for added fungal PME even though it will have been selected for some low pH activity. However, as long as there is some reasonable activity, this may not really matter, because the job of the enzyme is to strip methyl groups from the pectin to form pectate which eventually complexes with the calcium. Adding more PME may help it to happen faster, but probably won’t affect the final equilibrium outcome. However it will do no harm. (Eventually the PME will lose its effect due to slow denaturation and and binding with tannins, but this probably takes several days). 

As far as the demethylated pectin is concerned, its ionisation (as a weak acid) will be suppressed at low pH and therefore in theory it will be less able to form a complex with added calcium. However, whether this is significant in practice I do not know.  You could compensate for this by adding more calcium but as Claude points out there are legal limits in some places on the amount of calcium you can add. And there are practical limits too, because if there is too much calcium you can taste it as a certain saltiness / chalkiness and you don’t want that. If you are already getting a good gel, then you can go over the top by adding more calcium and frankly getting too much gel, the “bucketful” which you describe. 

I would say in practice, even at low pH, that you should not need to add any more calcium than the recommended maximum. I have personally found that is plenty to do the job in nearly all cases. But it may well be useful to add more PME if you can, simply to make the reaction happen faster. A slight temperature rise will also help, of course, but not so much as to encourage too much yeast growth. 

Finally, you should also look to the pectin content of the juice. For keeving, it is important that this should be sufficient to form a good gel. Maceration before pressing may help with this.  It may be the case that very acidic apples, or early apples, simply don’t contain enough soluble pectin to form a good gel. You can of course test this with the classical ‘alcohol precipitation’ test. 

Those are my thoughts. The whole process is multi-factorial and I’m not sure its possible to give rules of thumb. Practical experience counts for an awful lot. 

Andrew 

Wittenham Hill Cider Portal
www.cider.org.uk

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[Claude Jolicoeur]

Le mercredi 31 octobre 2018 06:01:00 UTC-4, Andrew Lea a écrit :

Well it is true in theory that some of the calcium added as calcium chloride could form (non ionic but soluble) calcium malate with free malic acid. But I’m not sure if there is any data to show how competitive that reaction is with the formation of the insoluble calcium pectate gel which is the desired outcome. Maybe Claude has some figures?

Not really. I have read about this in some of Rémi Bauduin's publication (not sure if in his book or some of the papers at IFPC). However if I remember correctly, this was only a qualitative statement, without any usable figures of how much calcium would be needed in function of pH.

I don't think any such study has been done.

Claude

[CiderSupply.com]

Over the years I've tried to keep track of the amount of PME and calcium chloride from year to year trying to control the amount of gel and it's seems to be definitely a 3-dimensional matrix of variables that effect one another. Without being able to hold all the cider variables constant from year to year, trying to match up CaCl2 with dependable predictions can lead one down the road to madness i think.

For the enzymes i use, I use 3g of PME to 11g of 97% pure CaCl2 24 hours later. Attached are past keeves in a photograph using largely the most similar bittersweet juices from year to year. The differences in type of keeves every year are radical.

Best regards
Chris Rylands

[Christian Stolte]

The Novoshape PME graphs show exactly what Andrew wrote.

On 31/10/2018 10:00, Andrew Lea wrote:

As far as the enzyme goes, it will certainly be less active at a lower pH.

A slight temperature rise will also help, of course, but not so much as to encourage too much yeast growth. 

[Claude Jolicoeur]

Le jeudi 1 novembre 2018 01:00:34 UTC-4, CiderSupply.com a écrit :

Attached are past keeves in a photograph using largely the most similar bittersweet juices from year to year. The differences in type of keeves every year are radical.

Chris, this is very nice photo montage...

However I am amazed by the small ratio of really successful keeves in there.

I wonder if it could have something to do with the glass carboy you use.

Last year I had a good keeve batch, but a bit too much for the vessel I had, so I transfered about 15 L into a glass carboy, and I thought it would be nice to make photos of the keeve process, so I installed the camera on a tripod, worked on the light, etc, so I could take one shot each day. Guess what - the chapeau brun never formed itself in the carboy, while the bulk of the batch in the plastic pail worked beautifully and made a nice chapeau. So that was same juice, same dosages, same temperature, only difference is container and size of batch.

What could make the difference? Why did I get a nice chapeau in the plastic pail and ont in the carboy?

- plastic vs glass?

- shape of container (plastic pail walls are not vertical)

- height of liquid in the container

I must say I was a bit perplexed by this.

Claude

[Christian Stolte]

Can you share how long you left the must to macerate and when you added the CaCl2 and the PME?

Beautiful Keeving shots

[Anders Klausen]

Thank you all for your contributions :) 

To Christian: I macerated 24 hours. Added the enzyme just after pressing. 24 hours later I added 0,9 ml CaCl2 per litre, 22 ml in total. It was a 36% soloution. The tempetature was 10C juring the first 24 hours. (But juring the next 7 days the temperature was arround 6C.) Before adding the Ca Cl2 I made a floculation-test and detected “some” sign of activity (I saw some particles that was not from the most, but not much)

As Andrew mentioned, adding a higer dosage of enzyme will maybe not help, but it will do no harm. Good to know. This batch (and the one I made next) was from the earlyest apples. They were a bit “floured” as I see a tendency to this year. Probably due to the dryest and sunniest summer in reccord.

All your reactions have been intresting to read, so I will just keep kalm and keeve on.

- Anders

[CiderSupply.com]

Hi Claude, actually the photo montage is a little confusing in the sence that not all photos were taken at final stage where the cap rose or right when I decided to rack.

They did end up as sucessful top keeves. My goal which i should have clarified when i compiled the photo was to show how different the keeving process looks like from batch to batch and year from year as keeving is underway.

I wanted to convey the importance of being patient and not to rack too soon just because the gel looks odd to be more patient to wait for the top keeve

What i am persinally discovering is that caps dont always have to rize to have a successful keeve. If PME and CaCl2 is used and the juice drops clear, that a bottom keeve can render identical juice to that of a normal keeve.

Now i just want to find a Mass Spectrometer service to compair juice from a bottom keeve, then wait for the juice to top keeve and compare the properties of both.

Something interesting on some of the photos where it shows the whole car boys completely gelled up, what I did was raise the temperature rom 42 Deg F to about 64F degrees and within 3 days the cap had compressed 90%. I've got some really great photos of how this progressed over this period. I tell people this and they are completely dumbfounded as to how compression can be up to 90% from a solid gel. In particular it was done with Mettais Bittersweet apples.

Picked very late season, macerated for 24 hours, ground almost to a fine applesauce, then pressed in a bladder press. the pme was added mixed very well and then 24 hours later the calcium chloride was added and mix well. The juice stayed cloudy and then all of a sudden 12 days later it completely gelled up then I moved it indoors and raise the temperature that's when the compression almost immediately started to happen.

Best regards
Chris Rylands