Keeving_101

[Will_D]

I am about to start up some keeving experiments.

So here goes a big post:

1.   What is Keeving?

In order to have a sweet cider it is necessary to have some sugar or sugar like non-fermentables in the finished cider. The later artificial sweetener methods are not used in traditional cider making. So if sugar is present there must be no yeast – this is why ciders are pasteurised and then sweetened with natural sugars – either from fresh juice of by using cane sugars.

However there is another way as traditionally used in the French cider making region of Normandy.

Here they grow apples on unfertilised land. The soil is so deficient in nutrients that the appleas also are very low in nutrients and they use the keeving process to remove even more nutrients from the apple juice (or must) so that the yeast gives up and can no longer ferment the still remaining apple sugars.

The process relies on the principle that pectin (naturally occurring in apple juice) can be persuaded to form a gel that:

1.  Removes the pectin which is a source of the haze in a cider that is slow to clear.
2.  Beneficially it also removes a number of proteins and amino-acids from the must that act as yeast nutrients

We then have a clear, nutrient deficient must that with luck will ferment to just the right level so that when the yeast stops working the cider is still sweet.
It is important to note that only the natural yeasts should be used – wine yeast/beer yeast or strong cider strains would all ferment out to dryness.
Originally this all happened naturally but now it is possible to buy the correct enzyme. This is Pectic Methyl Esterase (PME for short). It is used in conjunction with food grade Calcium Chloride.

Materials required:
I am using a keeving kit from the US [www.cidersupply.com].
Basically its a packet of PME(3 gms) and a packet of Calcium Chloride(11 gms) enough to treat 26 litres of juice.



Also as I am initially keeving pasteurised juice I have a small natural cider starter from a previous natural fermentation

The Pectin Test
In order to see how much pectin is present the juice take 20 ml of juice and add 10 ml of 94% ethanol. Methylated spirits will do. As will vodka I am told.

Stir it up and if there is pectin present then it will form a gel. The amount of gel is a measure of how much pectin is present. We need the pectin to help for the gelatinous cap – the "Chapeau Brun"

2.   Keeving pasteurised Juice

Process started 12/03/14

In order to help the process and make sure there is pectin present (and I had some apples over) I first scratted the apples:



The container was then purged with CO2 and then the pulp is then left alone overnight at a fairly low temeperature (about 6C).

Next day the pulp is pressed and checked for pectin as above.



As you can see on the fork it's a really thick gel so plenty of pectin

The pasteurised juice is also pectin tested:



Not as much as the fresh juice but even though the photo doesn't show it well a fair bit of pectin.

The pasteurised juice is then added to the pressed juice, mixed, the gravity taken and the pH measured

OG:    1.044  pH:   3.6

We are ideally looking for a gravity above 1.052 (ideally 1.055) and a pH of around 3.4 to 3.6. If using fresh pressed juice the recommendation is to use sulphite at half the normal corrective dose.

As the og was a bit low I added 600 gms of cane sugar to up the gravity by 10 points.
I did not add any campden tablets as pH was about right.

Then the PME is added all is given a good shake, moved into the cold garage. I will pitch the yeast starter after a few hours. (As the bulk of the must is pasteurised juice I am using a starter of natural cider yeasts). Ideally we need to ferment at around 8 – 10C as we want a long slow start to fermentation. This allows the pectin molecules to gel together and form the brown floating cap known as the "Chapeau Brun"



After a few days it's time to add the Calcium Chloride
This is dissolved in cooled boiled water (or fresh juice) and added to the must.

And now we wait for the "Chapeau Brun" to form. This can take up to 18 days or so. Its another game of patience.

NOTE: If the cap does not form no harm done. Just ferment as usual. Also another way to stress the yeast and make it give up is to frequently rack the cider from the sediment. Maybe once a week in the early more vigourous stages and then less frequently as the ferment slows down.

[Update] 14/03/14
Airlock just showing signs of activity. Its been 36 hours since start so now for the chloride:

Disolved the Calcium Chloride in boiled water, gave the cider a stir and added it. Bit more of a stir.

Note If using a glass carboy there not much that you can use to stir!! Used a length of SS rod

3.   Keeving natural fresh pressed Juice

This will have to wait till autumn!

[Eoin]

Nice one Will, was hoping you'd do a good job on this.

Sent from my HTC One

[@geterbrewed]

Will,

Great post!hope the pasteurised juice is a winner

[Will_D]

Apologies for the non mention of the source of the juice. Have been so busy with the techy. bit of the article!

Anys ways watch this space and hopefully it will be entered into this summers "Cider Ireland" competion. Along with a few others that I have "up my sleeve"

[Will_D]

Indeed I have Tube and a lot of other refs as well!

Have just updated the first post:

"
Airlock just showing signs of activity. Its been 36 hours since start so now for the chloride:

Disolved the Calcium Chloride in boiled water, gave the cider a stir and added it. Bit more of a stir.

Note If using a glass carboy there not much that you can use to stir!! Used a length of SS rod "

[RichC]

Excellent post Will!! Can this be done predictably enough to carbonate the cider naturally in the bottle?

[Will_D]

Excellent post Will!! Can this be done predictably enough to carbonate the cider naturally in the bottle?

Maybe:

If you are French, live in Normandy and have been making cider all your life as did Pere and GrandePere!!

In short I have no idea yet!

But have only researched the start of the procees - back end still to come!

[Leann ull]

Gonna give this one a go this year, be warned looking at the pics http://cidersupply.com/Page%20-%20Good-Bad-Ugly.html
it can be very tricky and you need cold temps

[cruiscinlan]

Would love an update on how this went for you will if you get a chance.