Multiple Early Rackings 1863 Style

[Patrick McCauley]

Hi All. I hope that your cider making is going well so far this Fall! I've asked this forum before about multiple rackings, and stalling fermentations to preserve sweetness(as described in Claude and Andrew's books), but I was wondering if anyone has tried racking the cider very very early in the fermentation process in order to clarify the juice and severely slow the fermentation down? I have never seen any books recommending this, but I got the idea from an 1863 article from Ann Arbor's Michigan Argus newspaper. The article recommends racking the cider after 5 days in the cask, and then continuing to rack it at similar intervals(but only on a clear day) for a total of 4 rackings, then allowing the cider to ferment for 2-3 months before bottling pet nat to create a sweet, champagne style cider. They even recommend adding pineapples to the cask! I've done this technique on a few of my blends this year, and so far the results seem promising. I racked them right at the first signs of wild fermentation starting, then racked again on those that were proceeding too fast. Despite the fact that they are early season ciders, I have been able to achieve super-slow, wild fermentations of very clear juice. It seems that this could give you similar results to keeving the cider. My only concern is that the fermentation could crap out too early, and leave an overly sweet, low ABV cider. Just wondering if anyone has tried this? I've attached the article for your reading pleasure.

Pat McCauley

[Claude Jolicoeur]

Yes, that is quite similar to what I routinely do...

I make the first racking once the foam has settled down and fill my carboys to leave minimal airspace. There is not a set number of days for this, simply because it is not all ferments that start at the same speed - some may take more than a week before fermentation starts to make a foam, so for these it would be nonsense to rack after 5 days.

However 5 days is possible for a batch that starts quickly, as it may have full foam by day 3, then the foam falls and the cider may be ready for its first racking by day 5 or 6.

On such quick starting ciders I agree that day 12 (more or less) can be a good moment for the second racking that has the purpose of slowing the fermentation. At that stage, the SG may be around 1.025 to 1.030 and you may have a FSU around 170 to 200, and half of this after the racking, so around 80-100 FSU.

A third racking may be done once the SG reaches 1.017 - 1.018, and this may be around day 20. Usually, this one really slows the fermentation down to about 15 to 20 FSU.

A fourth racking may then be done to stabilize the cider at the SG you choose. For example if you want to bottle at 1.012 to get a finished "pet-nat" at 1.008 (i.e. with about 18 g/L of residual sugar), you'd make this final racking at say 1.013, and it would then slowly finish at 1.012 and clarify. If I am in a hurry (for example sometimes I need the fermentation vessel for my late batch) I may add fining as I make this final racking.

I do insist in having a well clarified cider for bottling, as this greatly minimizes the amount of deposit in the bottles, and it also makes it easier to control the sparkle.

So, yes this yields a result fairly similar to keeving. But I do think keeving adds a little something to the flavor. Plus, the keeved ciders are so beautifully clarified - just for this it is worth the trouble.

As a general rule, I follow this procedure for my earlier batches, while I make my late batches by keeving. The reason is that keeving will not work on the earlier batches because of too warm temperatures, and the fact earlier apples start to ferment too quickly.

Also, note this will not work as well with commercially grown apples, as these are too rich in nitrogen to make it possible to use such traditional methods.

[Patrick McCauley]

Thanks, Claude! Most of my wild ferments take a week to a month to kick off to a visible, active fermentation. Is there some advantage to a very early racking, after a week or so, to remove all of the solids that accumulate at the bottom of the fermenter? I just screen the juice as a pour it into the fermenter to get all of the apple bits(and yellow jackets), and depending on the apple varieties used, the sediment can be quite heavy after a week in the fermenter. I have read that you get cleaner flavors by removing heavy solids from the must. I wonder if this early racking also removes some of the nutrients that the yeast feed on, and perhaps help to clarify the juice earlier in the process?

Pat

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[Claude Jolicoeur]

Le dimanche 31 octobre 2021 à 07:29:16 UTC-4, patrickmc...@gmail.com a écrit :

Thanks, Claude! Most of my wild ferments take a week to a month to kick off to a visible, active fermentation. Is there some advantage to a very early racking, after a week or so, to remove all of the solids that accumulate at the bottom of the fermenter? I just screen the juice as a pour it into the fermenter to get all of the apple bits(and yellow jackets), and depending on the apple varieties used, the sediment can be quite heavy after a week in the fermenter. I have read that you get cleaner flavors by removing heavy solids from the must. I wonder if this early racking also removes some of the nutrients that the yeast feed on, and perhaps help to clarify the juice earlier in the process?

What you say here is more like a pre-fermentation clarification. Also called Debourbage in French. 

Often, this is done with addition of a pectinase enzyme, and even by some cider makers, with addition of a fining. After a day or two, the juice will partly or entirely clarify, and there will be a lot of bourbes (sediments) in the bottom of the tank. The juice is then racked to the vessel where the fermentation will start.

This process does have many advantages, mostly as it permits to start the fermentation with a cleaner/clearer juice.

I don't think however this process by itself would reduce the nutrients - or only marginally.

However it does have some impact later on. You need to understand the yeast cells like to hang on some particles in order to remain in suspension in the fermenting must. If the juice is clarified, there are less such particles on which the yeast cell will stick,, and the result is there is a greater fraction of them that will remain in the bottom of the tank - and these will be eliminated by a racking. What this means is a racking will be more efficient in slowing the fermentation when the juice has been clarified before the start of the fermentation.

[Joshua Mahar]

I have been having good success with the method Claude is describing here. I will typically filter the juice into a bucket. Do the Sulfite treatment with Campden, either to "eliminate" wild or knock out the sub-yeasts in favor of the wild yeast we want and also treat with Pectic Enzyme. I will let this rest for a couple days (or three or five if I forget) in a cool place (50-60 degrees) and the result is rather clear/clean juice that I will pitch into and then rack into glass or steel. This also means that the first racking has a lot more packed lees rather than gross lees fresh from the pressing. This seems to work well with EC1118 too. 

Cheers

[Patrick McCauley]

Thanks Joshua and Claude! 

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[charles udale]

Thank you Pat for sharing this with us (you might be interested to know Dorothy Hartley - 'Food in England' - makes some similar points).

More generally, thank you to every one who posts on this forum and to Andrew and Claude for publishing their important insights into cider making. This is our first year of moderately large production and we have benefitted enormously from your collective wisdom. 

I have a couple of questions about multiple racking.

First, what is the theoretical justification for early rackings? It is commonly said that temperature and atmospheric pressure must be considered when planning to rack a cider which is still fermenting but why are high pressure and low temperature are preferable on a chemical and biological level. For instance, why does temperature cause yeasts to fall to the bottom of the tank? Or how much of the effect of racking is caused by the removal of yeast and how much by the removal of nutrients directly? I am very willing to accept they are intuitively but I would like to understand the mechanisms. Is there any scientific literature investigating the science of racking? I think this would help to understand the trade-offs cider makers face when they are not using temperature controlled tanks for instance. (i.e is it better to wait for a cold morning to rack even if the fermentation is allowed to progress further as a result?) 

Second, since in many cases cider makers are not using fancy equipment (I have been banned from spending any more money on our cider making project this year so a cooling plate will have to wait for next year unfortunately!), contributions to discussions such as this should probably include some description of key environmental variables at the time when the activities discussed were happening. For instance: Claude I believe you live in Canada. Depending on where you are in Canada (and the season), the temperature prevailing when you conduct your rackings might be very different to those prevailing in Rutland, England where I live. If temperature is an important determinant of yeast activity and concentration at the tank bottom, then your figures for FSU pre/ post racking may look very different from mine. I would be really interested learn more about these issues - do we know anything about the sensitivity of yeast concentration at the tank bottom to temp change? Are there threshold levels at which yeast concentration rises suddenly or is it gradual? 

Third, what about autolysis: yeasts consume nitrogen quite early in the fermentation process, right? But when they go on to die. Are they releasing this nitrogen back into the liquid? If so, over what time periods? The speed at which they release nitrogen (and potentially other nutrients?) should surely influence the decision about how regularly to rack. 

That brings me to a further question for Claude: why rack when the foam falls? I have read one paper which shows a drop of around 10 SG points is optimal (under certain conditions, using a filter to achieve precision etc etc) they argue the early take up of nitrogen is key here,  what is your justification? 

One final definitional / procedural question: what is racking? I would be interested to know if we are thinking about this in the same way. The paper I just mentioned uses an expensive filtration system and then reintroduces some of the removed yeast to achieve an exact decimal reduction. More people on this forum (I dare bet) are syphoning or pumping liquid from one tank to another (thats what we do). For those of you following this more primitive method: how much liquid do you leave? Do you go right down to the lees or do you leave some additional liquid, perhaps on the assumption that yeast concentration increases gradually the closer to the bottom of the tank one gets. Also, what about all that CO2 that is released - might this not have a detrimental effect on the speed of fermentation (assuming the aim is to slow it down) since yeast do not thive in high CO2 environments. Would removing this CO2 allow them to metabolise sugar faster?

I am very interested to hear your thoughts on this, 

All the best, 

Charlie 

[Claude Jolicoeur]

Lots of questions there... I won't try to answer everything but a few points.

Le vendredi 19 novembre 2021 à 09:49:18 UTC-5, charle...@gmail.com a écrit :

First, what is the theoretical justification for early rackings? It is commonly said that temperature and atmospheric pressure must be considered when planning to rack a cider which is still fermenting but why are high pressure and low temperature are preferable on a chemical and biological level. For instance, why does temperature cause yeasts to fall to the bottom of the tank?

To be frank, I personally don't care about temperature and atmospheric pressure. I rack when I feel it is time.

Or how much of the effect of racking is caused by the removal of yeast and how much by the removal of nutrients directly?

Direct removal of yeast cells will cause an instant reduction of speed of fermentation (if you remove half of the living cells, FSU should be divided more or less by a factor of 2).

Removal of nutrients will affect the rate of multiplication of yeast, hence the slope of the curve of FSU vs time. If there is less nutrients, the speed will decrease gradually even if rackings are not done.

You however need to understand that nutrients can't be removed directly. We need the yeast to take the nutrients, and then by removing the yeast, we remove some nutrients - about 10% of the weight of yeast cells is nitrogen.

Third, what about autolysis: yeasts consume nitrogen quite early in the fermentation process, right? But when they go on to die. Are they releasing this nitrogen back into the liquid? If so, over what time periods? The speed at which they release nitrogen (and potentially other nutrients?) should surely influence the decision about how regularly to rack. 

Yes, the nitrogen from dead cells is released back to the fermenting cider and will be used as nutrients for the living cells and for remultiplication.

 

That brings me to a further question for Claude: why rack when the foam falls? I have read one paper which shows a drop of around 10 SG points is optimal (under certain conditions, using a filter to achieve precision etc etc) they argue the early take up of nitrogen is key here,  what is your justification? 

 

This is mainly a practical issue.  I start the fermentation in a large plastic pail with enough headspace for the foam. When the foam falls, I can then rack in a carboy with very little headspace without risk of making a mess.

I'd say that usually about 25 to 30% of the sugar has been fermented when I make this racking. Naturally, this does also have an impact on the speed of fermentation as some yeast is left behind.

For those of you following this more primitive method: how much liquid do you leave? Do you go right down to the lees or do you leave some additional liquid, perhaps on the assumption that yeast concentration increases gradually the closer to the bottom of the tank one gets.

I leave the minimum liquid possible.

[Patrick McCauley]

Charlie,

Because I am a luddite, and because I am "only" making a 150 gallons or so a year, I just keep it simple. No filtering, fining, pectic enzyme or fancy temperature controls. I just use a simple raking cane. The temperature can really be an issue for my early ciders, as my cellar can be 68 degrees Fahrenheit(20 Celsius). This year I tried to avoid as many early apples as I could for this reason, except the abundance of crabapples we have at that time. By October, our temps here in Ann Arbor, Michigan, USA regularly get down to freezing at night, so I will open the window at night and close it during the day when they warm up. 

What I do prior to racking is open the window wide at night to cool things off as much as possible, and then rack in the morning when in theory the cider is about as cold as I can get it. At least visually, this seems to really slow the ferment(or at least the amount of bubbles I can see). I've also noticed that the cider is clearer when I'm using crabs, late season apples and proper cider fruit vs.  over-ripe dessert apples, like Golden Delicious which are easy to find around here. Claude or Andrew could probably explain why these ciders start out so much clearer. The abundance of dessert apples and temps early in the season being warmer than I like, are part of the reason I have started doing a very very early racking on my ciders(sometimes followed by another racking a week or two later if it's still going to fast). I'll keep you posted on my results when they are in during 2022 bottling time. Good luck with your cider making!

Pat

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[charles udale]

Thank you for your responses Claude, lots to think about! 

One of the reasons I ask about temperature is because I am concerned that you may be able to stop the fermentation prematurely through multiple rackings because it is suitably cold where you live. Whereas, for the early pressings at least, it is warm enough here to keep the yeasts more active and thus in suspension. This might mean you remove a greater proportion of the yeast than is possible when conditions are warm(ish) like they have been for us the last month. 

We have one barrel currently reaching the end of fermentation (sg = 1004) that we have racked five times (first rack at reduction of 10 points, OG = 1048 so - c.20%). We kept some of the same juice separately and did not rack it. Whilst the barrel fermented more slowly we are not completely convinced the difference was caused by racking since the smaller container with the non-racked juice would be more sensitive to temperature changes - heating up more in the day. Also, despite the barrel fermenting more slowly, it still reached speeds of 300 FSU and FSU did not change significantly after racking. We think this may be because temperatures we still in the 10-16 range. 

Does this sound plausible? 

[charles udale]

Thanks for your message Pat! 

As you will see from my response to Claude, I have had a similar temp problem recently. I am taking the same approach as you from now on. This coming week we are in for c.0 degrees C over night so we are planning to get up very early in the morning and rack after the second day of these temperatures. 

I think investing in a cold crash set up (cooling plate and beer cooler combo) could eliminate much of the early fruit problem by facilitating near freezing temps for a day or two before racking even in late summer early autumn. Have you (or any one else for that matter) considered this?

On temperature: I would be interested to hear if anyone has done any experiments using fermentation vessels of different sizes or materials. I would imagine bigger = more consistent but how much more? Plastic will insulate to a greater extent than steel, but not sure if this is always means steel is preferable since the juice will be subjected to larger variation as a result? 

Pat, please do keep me posted. I will do the same. 

[Andrew Lea]

What sort of apples do you use and do you know anything about their nutrient levels? Without nutrient-poor fruit, even multiple rackings will not do the job you wish. Also, are you using wild yeasts or cultured? 

(Apologies if you have already answered these questions, but I have missed them if so).

Andrew

Wittenham Hill Cider Portal
www.cider.org.uk

On 19 Nov 2021, at 16:53, charles udale <charle...@gmail.com> wrote:

Thank you for your responses Claude, lots to think about! 

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[luis.ga...@gmail.com]

Here is my experience with Claude's method that I use since the beginning of my cider journey.

1) I use exclusively uncultivated apple trees (old unfertilized standard trees and wildings). I tried twice to do this technique with apples from commercial orchard with no success.

2) For some reason, some varieties of apple, even uncultivated, are too nutrient-rich and with these, it is impossible to make a cider with residual sugar (no matter how may racking you do).

3) With early apples (pressed before the third week of september), it is hard to maintain residual sweetness in the final cider. Temperature clearly play a role in this and I feel that these apple are also richer in nutrient than later maturing apples.

4) Natural fermentation (without added yeast) have a clear effect on the speed of fermentation. One cider made this year with yeast shows a FSU of 240 after 17 days of fermentation using a commecial yeast. All my other blends of similar apples pressed the same day fermented naturally had a FSU of 50 to 120, much easier to slow down.

5) One to three racking are usually enough to achieve a medium to semi-sweet cider.

6) Too early racking is not very usefull, because it has little effect on fermentation speed. I think the cider is racked off too little dead yeast (and therefore, too little nutrient). I monitor fermentation and wait for at least 25 % of gravity point drop to rack (like Claude).

Louis

[charles udale]

Thanks Andrew and Louis, 

We are using wild yeast and we have no idea about nutrient levels (is there a cheap way of measuring YAN?). The batch I was describing a number of eating apples selected for their acidity (we have a surplus of bitter sweet juice for which we need to reduce the PH). Almost all came from unsprayed / fertilised trees, though some came from an orchard which is used as a horse paddock so plenty of fertiliser there presumably! 

I understand the nutrient levels will affect the multiple racking method but does it make it unviable or does it just mean more rackings / colder temperatures at racking are needed? If I understand this correctly: 1. fixed quantity of nitrogen in juice; 2. yeasts take up nitrogen in order to grow (and release it again when they autolyse); 3. yeasts also die during fermentation so, without the ability to grow (multiply), their population will decline after all nitrogen has been consumed 4. racking removes only those yeasts (alive and dead) which are out of suspension; 5. the proportion of all yeasts in the tank that are in suspension whilst fermentable sugar remains is related to the temperature of the juice - perhaps because they are being pushed around the tank on the currents generated through CO2 release?

If this model is correct it suggests: racking removes yeast, which reduces population size and therefore the rate at which the population as a whole can metabolise sugar. Racking also removes the nitrogen which these yeast contain which means less nitrogen returned to juice for future population growth when yeast autolyse (any ideas about the significance of this process for yeast population sustainability?). Because yeasts are also dying throughout fermentation, in low-nutrient juice (where the yeast population consume most or all yeast assimilable nitrogen early on in the fermentation process) the population cannot recover after racking because there is no more nitrogen and the pressure of mortality means the population begins falling, ideally so much that the population dies out before all sugar has been consumed. However, if yeast assimilable nitrogen remains in juice after racking, the yeast population can recover, continue to grow, or such a small proportion is not in suspension (perhaps because of the vigour of the fermentation - itself in part an outcome of the size of the yeast population) that racking only removes a small proportion of the total population. Thus the population may be temporarily slowed but their recovery will ensure all sugars can still be consumed => no residual sweetness despite multiple rackings.

But, there is still a fixed quantity of nitrogen in the juice and racking is still removing some yeast (and thus immediate fermentation potential of the colony) along with some of their nitrogen (future growth potential). So, does this not just mean more yeast need to be removed from the juice either by: 1. more rackings or 2. more efficient yeast removal by lowering temperature and pushing more yeast out of suspension before racking? To take an extreme example, if yeast were removed through sterile filtration, would the nutrient content of the juice not become irrelevant? After all, the whole (or very nearly the whole) colony would be removed at exactly the specific gravity one requires. Could a small proportion of that yeast population not be reintroduced such that one could bottle pet-nat?

One final thought: does anyone know how racking affects the make up of the yeast population that remains? There could be a sort of 'unnatural selection' where the yeasts that are most likely to fall out of suspension are the most vulnerable to be racked out of the liquid. If the fermentation is wild and thus is potentially the result of multiple yeast strands might this process be causing some kind of selective effects which affect the character if the cider? Any papers on this? 

[Claude Jolicoeur]

Le lundi 22 novembre 2021 à 13:27:51 UTC-5, charle...@gmail.com a écrit :

I understand the nutrient levels will affect the multiple racking method but does it make it unviable or does it just mean more rackings / colder temperatures at racking are needed? If I understand this correctly: 1. fixed quantity of nitrogen in juice; 2. yeasts take up nitrogen in order to grow (and release it again when they autolyse); 3. yeasts also die during fermentation so, without the ability to grow (multiply), their population will decline after all nitrogen has been consumed 4. racking removes only those yeasts (alive and dead) which are out of suspension; 5. the proportion of all yeasts in the tank that are in suspension whilst fermentable sugar remains is related to the temperature of the juice - perhaps because they are being pushed around the tank on the currents generated through CO2 release?

I think you have a pretty good summary there. I would add in point 5 that an initial clarification of the cider would also reduce the proportion of the yeast cells that are in suspension.

But, there is still a fixed quantity of nitrogen in the juice and racking is still removing some yeast (and thus immediate fermentation potential of the colony) along with some of their nitrogen (future growth potential). So, does this not just mean more yeast need to be removed from the juice either by: 1. more rackings or 2. more efficient yeast removal by lowering temperature and pushing more yeast out of suspension before racking?

Yes this approach is seen for example with many producers in France who by filtering of centrifugation will eliminate a certain fraction of the yeast cells that are in suspension. Some of the more technically oriented will use a microscope before racking to count the number of cells per mL, and from this deduce they should filter a certain percentage of the cider - for example they could let 25% of the cider pass without filtering and for the rest they would eliminate the in-suspension yeast cells.

[Andrew Lea]

> To take an extreme example, if yeast were removed through sterile filtration, would the nutrient content of the juice not become irrelevant? After all, the whole (or very nearly the whole) colony would be removed at exactly the specific gravity one requires.

I have met cidermakers in Australia doing that with dessert fruit / cultured yeast fermentations. They use winemaking tanks which they chill to zero degrees to halt fermentation at say SG 1.020, followed by cross-flow and then sterile filtration. They then artificially carbonate the cider and use Velcorin as a yeast inhibitor at bottling. Some instead use Charmat tanks under pressure to keep the natural sparkle. But they still need a yeast inhibitor. The soluble nutrient content remains relevant while any yeast is active.

> Could a small proportion of that yeast population not be reintroduced such that one could bottle pet-nat?

No, because as long as sufficient soluble nitrogen remains, fermentation and uncontrolled yeast growth will start up again.

Have you not considered keeving? One of its advantages over simple repeat racking is that it actually removes a good deal of soluble nitrogen onto the pectin gel at the outset. So you start at a better place.

Andrew

Wittenham Hill Cider Portal
www.cider.org.uk

[luis.ga...@gmail.com]

But, there is still a fixed quantity of nitrogen in the juice and racking is still removing some yeast (and thus immediate fermentation potential of the colony) along with some of their nitrogen (future growth potential). So, does this not just mean more yeast need to be removed from the juice either by: 1. more rackings or 2. more efficient yeast removal by lowering temperature and pushing more yeast out of suspension before racking? To take an extreme example, if yeast were removed through sterile filtration, would the nutrient content of the juice not become irrelevant? After all, the whole (or very nearly the whole) colony would be removed at exactly the specific gravity one requires. Could a small proportion of that yeast population not be reintroduced such that one could bottle pet-nat?

Theorically, I guess if you were able to remove a certain amount of yeast as fast as they are multiplying, you could slowly depleate the cider's nutrient content and obtain a cidre with residual sugar. This is not feasible for a small producer and I am not even sure it would be for a large one.

To give you an example, my last cider done with commercial apple was 50% my apple and 50% commercial apple. The commercial apple were tested at around 100 ppm YAN (suposidly not that high for commercial apples). It was inoculated with a yeast (which added some YAN). In a fermentation done in winter at 6-8 deg. celcius including 3 racking (one at day 10, ont at day 17 and one at day 30), I was not able to maintain sugar levels in this cider. If you do the same exercise with a cider made with 100 % commercial apples (from Andrew's website, YAN can be over 250 ppm in some cases), I hardly see how you could reduce YAN level by any mean to obtain a naturally sweet cider. 

Here is an interesting blog on keeving, based on the visit of some cider producers from the US to France and UK (mainly based on the keeving process, but some aspects like the filtration to remove yeast and slow fermentation is included). 

https://www.nwcider.com/keeving/

Louis

Le lundi 22 novembre 2021 à 13:27:51 UTC-5, charle...@gmail.com a écrit :