Questions about Sulphite (again)

[doublejef]

Hello there,


I have an opportunity to get some fresh pressed apple juice from a orchard this next winter. So I'm making all my plan to be ready when the time will come.

Most part of the question I'm still asking myself are about sulphite and I would like to opinions on some specific point.


But first, here comes what I get from all my research into all your message, thanks a lot for all the info provided.

Sulphite does 3 things, it kills bacteria, it stop yeast reproduction and it prevent oxidation and so improve shelf live.


To kill bacteria, we need the molecular SO2 level to be on the 0.4-0.8mg/L range

To prevent oxidation, we want the free* SO2 level to be on the 30-100mg/L range

For all those two purpose, we use Potasium Metabisulfite (campden) or Sodium metabisulfite (?). Calculation must be done including the pH level of the juice for example with this tool : www.fermcalc.com/FermCalcJS.html

So this part of the job must be done before pitching a selected yeast to kill the other competitor in the juice and every time the free SO2 level is too low.


To inhibit (not kill) the yeast grow we Potassium Sorbate (k-meta). But is it sulphite ? So if we rack our cider and let all the yeast behind, even if we add fermentable sugar, yeast will not be able to come back and eat it.

Is that correct?


Now I have to decide when and why I should or should not use all those chemical product in my process and would love to have advice on it.


- I have to make some road with the bucket full of juice in my car, so will campdem helps to prevent from oxidation or is it useless because yeast will need O2 to grow and will eat it protecting the juice?

- I don't want too much funkiness in my final product and since I can't control what happened to the apple before I get the juice I have no choice but using selected yeast. So campden once again is the easy way. But If I pitch a good healthy yeast just as I get my juice, what is the risk? Even if the natural yeast are also in there, their impact will be quite light and just add some complexity or I'm a fool to think that?

- Once I add campden into a closed bucket with apple juice, does it mean that (if bucked is clean) I can keep this juice like this for a while and ferment it later? Like weeks or month?

- If I add sulphite before fermentation, does it also play the conservative and anti-oxidant role during the whole time including in the bottle (long shelf live) or does it need a new addition post-fermentation? Do you think it's a good idea to buy a kit that can give me the SO2 concentration and test the cider once in a while to be sure the free SO2 level is ok? Any example of good quality kit?

- I know campden can be tasted in cider. Is it the SO2 that we taste or another component. If it's SO2, solution should be to always stay under a certain level of free SO2 by measuring it?

- K-meta is it SO2? Is it also known allergic trouble possibility with it?

- Is there any books out there that I should read about this?


I recently had the chance to find a bottle of cider coming from the Tom Oliver's Cidery who is a kind of final boss of the game and I was surprised to see on the bottle that it contained sulphite. It surprised me because I know he never add yeast into his cider (so he doesn't add sulphite before fermenting) and the cider was not still so that means sulphite is not use to kill the yeast before bottling (except if the guy make forced carbonatation but I don't think so). So I guess it's just SO2 to help shelf live.


A lot of question and maybe not really well written. Thanks and sorry.


*Free SO2 is the portion that is not bound with aldehydes, sugars or other oxidizable substances in the wine, is the form that is available for anti-oxidant protection and anti-microbial activity. Free SO2 will disappear over time into a wine, binding with the above-mentioned substrates, causing the ability of a wine to retard oxygen and microbes to decline as well.

 

[Maylar]

From a practical standpoint, sulfite in raw pressed orchard cider will inhibit wild yeast only for a few days, unless you freeze it. I dunno how that applies to pasteurized juices, as I don't use any.

For the rest of that, you need this guy: @RPh_Guy

 

[Hanglow]

Have a read of this, it's useful. See the bit on sulphites which will answer some of your questions too

http://www.cider.org.uk/frameset.htm

 

[RPh_Guy]

Wow, lots of good questions!

Sulphite does 3 things, it kills bacteria, it stop yeast reproduction and it prevent oxidation and so improve shelf live.

Maybe, no, and yes.

1. Sulfite can kill bacteria, but some bacteria are pretty tolerant of sulfite levels to some degree.
2. Sulfite does not stop "yeast reproduction" unless it outright kills them, which is dependent on the dosage and strain.
3. Sulfite does indeed prevent oxidation, which is the main reason to use it.

To kill bacteria, we need the molecular SO2 level to be on the 0.4-0.8mg/L range

Well...
The amount needed to kill wild yeast and bacteria is typically at least 1ppm molecular SO2 (although some wild yeast and/or bacteria may still survive). The amount of molecular SO2 depends on the pH and amount of free SO2, which in turn depends on the amount on binding potential on the juice, which can be pretty unpredictable.

Around 0.5-0.8ppm molecular SO2 is the minimum amount needed in the bottle to inhibit wild microbes, which occurs at the time of serving. This is in the presence of alcohol and tannins (which are both anti-microbial).

To prevent oxidation, we want the free* SO2 level to be on the 30-100mg/L range

Yep!

For all those two purpose, we use Potasium Metabisulfite (campden) or Sodium metabisulfite (?). Calculation must be done including the pH level of the juice for example with this tool : www.fermcalc.com/FermCalcJS.html

Perfect!
You must have read some of my posts.

K-meta is generally preferred because potassium is flavor-neutral, although sodium isn't necessarily bad.

Edit: You need to look at the Campden product to see which salt it is. Mine are sodium metabisulfite.

So this part of the job must be done before pitching a selected yeast to kill the other competitor in the juice and every time the free SO2 level is too low.

Yes, use sulfite before fermentation if you're using unpasteurized juice and want to kill the wild microbes, which arguably isn't needed but some people prefer.

After fermentation, sulfite is helpful to prevent oxidation and reduce wild microbe activity, but only if you aren't naturally carbonating your cider/wine. You should strive to maintain adequate sulfite level during aging of a still or force carbonated cider/wine.

To inhibit (not kill) the yeast growth we use potassium sorbate (K-meta). But is it sulfite? So if we rack our cider and let all the yeast behind, even if we add fermentable sugar, yeast will not be able to come back and eat it.

Sulfite and sorbate are completely different.
Potassium metabisulfite is "K-meta". This is a form of sulfite (along with sodium metabisulfite).

Potassium sorbate (which forms sorbic acid) inhibits yeast growth. It is not sulfite.

Correct use of sorbate to stabilize a wine for backsweetening involves clarifying the wine, racking off of the yeast, and then adding the correct concentration of sorbic acid, based on the alcohol level.
Sorbate should always be used in conjunction with sulfite.

If you do not intend to backsweeten, sorbate is not needed.

If you use sorbate, the cider/wine will not naturally carbonate, so it will be still or otherwise need to be force-carbonated.

I have to make some road with the bucket full of juice in my car, so will campdem helps to prevent from oxidation or is it useless because yeast will need O2 to grow and will eat it protecting the juice?

Is the juice pasteurized? There's absolutely no reason to use sulfite before fermentation. You should pitch yeast ASAP.

Is the juice unpasteurized? You may or may not want to use sulfite, depending on your preference.

Either way to should thoroughly aerate the juice before pitching your desired yeast.

If you are using unpasteurized juice, you have the option of using different levels of sulfite for varying degrees of microbial inhibition. You can fully inhibit wild microbes with 1ppm molecular SO2 or higher, or no inhibition of wild microbes and let them fully conduct the fermentation, or anything in between.

- I don't want too much funkiness in my final product and since I can't control what happened to the apple before I get the juice I have no choice but using selected yeast. So campden once again is the easy way. But If I pitch a good healthy yeast just as I get my juice, what is the risk? Even if the natural yeast are also in there, their impact will be quite light and just add some complexity or I'm a fool to think that?

A natural fermentation doesn't necessarily produce "funk". My 100% wild ciders have been pretty clean (and amazingly delicious).

You haven't indicated whether it's pasteurized somehow, which makes a big difference regarding your plan. Many cider mills will UV pasteurize or add some kind of preservative, because unpasteurized sweet cider is potentially dangerous to drink.

If it's unpasteurized and you want only the plain flavor of your preferred yeast, the best course of action is to use 1ppm molecular SO2 pre-fermentation for 24 hours, aerate like crazy, and then pitch a good amount of healthy yeast. Post-fermentation you should rack relatively soon. Your plan from there depends on your packaging process.

- Once I add campden into a closed bucket with apple juice, does it mean that (if bucked is clean) I can keep this juice like this for a while and ferment it later? Like weeks or month?

No. Sulfite does not preserve a juice indefinitely, unless maybe if you add a very high amount of it.

- If I add sulphite before fermentation, does it also play the conservative and anti-oxidant role during the whole time including in the bottle (long shelf live) or does it need a new addition post-fermentation? Do you think it's a good idea to buy a kit that can give me the SO2 concentration and test the cider once in a while to be sure the free SO2 level is ok? Any example of good quality kit?

Any sulfite added pre-fermentation should be completely removed (forming sulfate) via aeration prior to pitching. So, no, it will not continue to have beneficial effects -- sulfate increases perception of dryness.

If you are into cider/wine making and don't mind a little chemistry lab work, I highly recommend using the aeration-oxidation method of sulfite testing. It's the gold standard for measuring free SO2 (sulfite).

This is a great kit:
https://www.morebeer.com/products/economy-aerationoxidation-free-so2-test-kit.html
I think it could do without the 10mL pipette if you wanted to bother assembling it yourself and have a different way to measure 10mL (without needing high precision).

- I know campden can be tasted in cider. Is it the SO2 that we taste or another component. If it's SO2, solution should be to always stay under a certain level of free SO2 by measuring it?

Molecular SO2 can be tasted above the 1.0-1.2 ppm range. It can supposedly give a "burnt match" aroma, but moreso it causes a noxious choking sensation.

Free sulfite (bisulfite ion) can allegedly be tasted above the 100ppm-ish range although I'm not sure if that's actually true. It certainly has no aroma based on my testing but I haven't tasted levels that high.

K-meta is it SO2? Is it also known allergic trouble possibility with it?

"K-meta" is potassium metabisulfite. When added to water it produces potassium ion and 2 bisulfite ions.

At the risk of over-simplification, no, there's no "allergic trouble" with it unless maybe if you have asthma.

A lot of question and maybe not really well written. Thanks and sorry.

Umm? I should make a website.
This is obviously a complex topic. I'm unaware of any thorough and accurate source of this info. Claude Jolicoeur's book The New Cider Maker's Handbook is ok, and contains pretty reasonable info, if not always practical or covering a wide range of possible processes.
The info about sulfite levels is probably not applicable to American cider apple varieties because our apples have a lot less tannins..
I plan to do some testing myself next apple season, but without a $$$ dissolved oxygen meter it won't be as scientifically rigorous as I'd like.

I was surprised to see on the bottle that it contained sulphite.

Why would you be surprised? Sulfite is completely necessary for preserving the flavor of wine by preventing oxidation and microbial activity. It's in >99% of commercial wines.

the cider was not still so that means sulphite is not use to kill the yeast before bottling (except if the guy make forced carbonatation but I don't think so).

I'd wager it's force carbonated. Basically no commercial products are fully bottle carbonated.

Hope this all makes sense
Cheers.

 

[SEndorf]

Wow! A very thorough and information packed response. Thanks

 

[doublejef]

Wow thank you some much for taking the time to answer with so much accurately. It’s a lot of information’s.

First, I indeed forget to say that the juice I will buy will be unpasteurized. I could ask for pasteurized juice but I heard that it will be flavourless and also decrease in quality during time once fermented.

I also should tell you that I live in Belgium so, I’m a 3 hours drive from Normandy and the standard there is 100% apple juice without anything but apple juice (no yeast added, no chemical, not event nutrients).

This cider must be drunk within a year after sale and it is often quite funky and sometimes with flavour that would be considered as default in the world of beer where I’m from. Dust, smoked, leather, manure,… I prefer clean cider by far (or the funky fruity side of the brett).

I would love to make natural fermentation if I was sure to have clean cider at the end. You say your 100% wild cider is clean but do you have some tips to conduct a wild but clean fermentation? In my case I can’t control how the apple has been washed, pressed and all the natural yeast in the press area should change every year so it seems like lottery to me. Don’t you think?

But so far, reading your lines, I feel less and less like I will add sulphite before fermentation. Piching the yeast ASAP and hope for the best.

There are two more point I’m not sure I understand :

Around 0.5-0.8ppm molecular SO2 is the minimum amount needed in the bottle to inhibit wild microbes, which occurs at the time of serving. This is in the presence of alcohol and tannins (which are both anti-microbial).

You mean that this level should be naturally in a fermented cider if there is enough alcohol and tannin from the apple? And if it is not the case what can wild microbes do to the cider into the bottle if there is no more sugar and neither O2?

If it's unpasteurized and you want only the plain flavor of your preferred yeast, the best course of action is to use 1ppm molecular SO2 pre-fermentation for 24 hours, aerate like crazy, and then pitch a good amount of healthy yeast. Post-fermentation you should rack relatively soon. Your plan from there depends on your packaging process.

Why in this specific case should I rack quite soon? I’m sure there is a good reason but can’t figure it out.


For the rest I will definitely buy some equipment to control the SO2 level during all the process and before racking and bottling. I already seen the book from Claude Joli Coeur after watching his speech on YouTube, I’ll order as soon as I’m done writing.


Once again, thanks a lot for sharing all this.

 

[RPh_Guy]

You say your 100% wild cider is clean but do you have some tips to conduct a wild but clean fermentation? In my case I can’t control how the apple has been washed, pressed and all the natural yeast in the press area should change every year so it seems like lottery to me. Don’t you think?

It's definitely unpredictable.
You can do a wild fermentation and there are things you can do to limit or prevent barnyard funk:

1. Racking soon after fermentation completes
2. Adding sulfite post-fermentation.
3. Keep fermentation temperature fairly low, 16°C (60°F) or lower.

I feel less and less like I will add sulphite before fermentation. Piching the yeast ASAP and hope for the best.

Make sure to pitch healthy yeast; that means making a starter for liquid yeast or properly rehydrating and attemporating dry yeast.

You mean that this level should be naturally in a fermented cider if there is enough alcohol and tannin from the apple? And if it is not the case what can wild microbes do to the cider into the bottle if there is no more sugar and neither O2?

If you want to use post-fermentation sulfite (and aren't naturally carbonating), you should maintain levels of molecular SO2 above 0.8ppm to inhibit wild microbes.

Sulfite is neutralized by oxygen, so once the cider is bottled, the sulfite level will decline and you will no longer be able to increase it. Therefore the lowest level it will reach is at the time it is consumed. Your target level at that point is around 0.5-0.8ppm.
I hope this makes sense.

Brettanomyces and possibly other wild microbes do not need sugar or oxygen to add flavor.

Why in this specific case should I rack quite soon? I’m sure there is a good reason but can’t figure it out.

The lees are a source of nitrogen and other compounds that will feed wild microbes.
The barnyard funk mainly comes from Brettanomyces eating decaying cells.

The delicious fruity Brett flavors are created rather early, within the first 1-5 months. If you wanted, you could rack and add sulfite when it reaches your desired funky profile.

 

[doublejef]

Ok something new I didn't know about the Brett and the lees. I was also thinking about buying a barrel and make some guard and batonage, but, reading you, I understand that it could actually give me a result I don't like.

I also realize that forced carbonation is quite unavoidable for all the cider I want to get a long shelf live. That’s something I can manage for some gallon but it change the bottling process of bottling. Or I can buy a pressured tank and carbonate during fermentation. Or I can pasteurize after bottling which is way easier but probably doesn’t protect the cider against oxydation.

So much possibilities, so much question in my head.
Is it noticeable I’m turning a bit mad ?

More seriously, I think I could do like this :

Get the juice, split it into 2 separate bucket.

Bucket 1, I let it go by itself, adding nothing but hope, fermenting around 10-15°C. Once fermentation is done, I rack it clear and let it age (maybe in oak barrel) for 3-5 month before adding priming sugar and bottling.
100% Wild, no sulphite.


Bucket 2, I pitch an healthy yeast as soon as I can. I will choose a yeast that can let a minimum of residual sugar like a sweet mead or something but I also want one that can ferment under 16° to create an environment where Brett are not happy (still looking for this yeast). Once fermentation is done, I cold crash, put sulphite in it (after measurement of the SO2 level already in it) and rack it clean. I send it for aging and when the SO2 is back down, I pitch a new neutral yeast, add priming sugar and send it to bottle fermenting if I want it carbonated and without sugar if I want it still.

Does it seems correct as a process ? Good idea to sulphite before and not after racking to protect from oxidation during it? Does it make sense to sulphite at this point to kill bacteria’s and wild yeast before aging? The plan to pitch yeast for carb bottling is realistic?

 

[RPh_Guy]

I was also thinking about buying a barrel and make some guard and batonage, but, reading you, I understand that it could actually give me a result I don't like.

If you maintain a good sulfite level and minimize oxygen exposure, it would probably be fine if you wanted to do that.

Does it seems correct as a process ?

Your plan could work, but I think the best option for your goals might be filtering. After clarification you can physically remove the microbes with a small enough filter (0.45 micron). After filtering you could then force carbonate or add yeast and sugar to naturally carbonate.

By the way, you can lower the sulfite level in a controlled manner with a specific amount of hydrogen peroxide.

Definitely lots of options

 

[doublejef]

Just a quick update to say that I received the book "New Cider Maker's" and already read half of it.
It's great, very accurate and specific. A big help for sure to those who want to make cider with good knowledge of the process and all the possibilities’.
I'll make a quick review of what I learned in it here in a few days.

 

[Blacksmith1]

Umm? I should make a website.

That or write a post that can be closed and stickied. You should PM Yooper or one of the other admins about this. Otherwise you will be answering the "sulfite posts" till you leave or die because all us mere mortals will keep deferring to you on this subject.

 

[RPh_Guy]

That or write a post that can be closed and stickied. You should PM Yooper or one of the other admins about this. Otherwise you will be answering the "sulfite posts" till you leave or die because all us mere mortals will keep deferring to you on this subject.

https://***************.com/wiki/Sulfite
(In progress)

 

[doublejef]

Hello there,

I made my homeworks during the last weeks and I learn a lot from different sources. I already finish the book of Claude Jolicoeur (The New Cider Maker's) and I should say it is a must read book. I also starded "Craft Cider Making" from Adrea Lea and it is also a good source of info. This also open some new question in my mid but I think I will open a new thread about that.


As we are here talknig about sulfite, I still would like to ask something.
If sulfite doesn't stop yeast reproduction as sorbate does, it only can stop fermentation killing outright the yeast, I guess we use sorbate and sulfite to add less of the quantities of both. Is it right.
If it is, that means it is possible to sulfite a fermented cider with a very little amount of Spotassium metabisulfite and so it will be protected of oxydation but will, with time, referment in bottle if priming is added.
For example, if I make a cidre de glace with a OG 1135 and I want to stop it @ 1050. I make some racking to clarify and add K-meta up yo 1ppm when I reach 1050. Is it a chance it will make me bottle bomb without sorbate ?

Last question, I'm looking for a TA titration kit to and I found some kit designed for wine that can also give SO2 free level like this one :
https://www.brouwland.com/en/our-pr...measurement/d/acid-test-kit-vinoferm-complete
I guess it does fit to cider as it is design to work with tartric acid and not malic.
Something like this does it exist for cider ?

 

[RPh_Guy]

I already finish the book of Claude Jolicoeur (The New Cider Maker's) and I should say it is a must read book. I also starded "Craft Cider Making" from Adrea Lea and it is also a good source of info.

Lea (and Jolicoeur, who just copied from Lea) both present inaccurate information. Check out the article I wrote it you want reliable info.

If sulfite doesn't stop yeast reproduction as sorbate does, it only can stop fermentation killing outright the yeast, I guess we use sorbate and sulfite to add less of the quantities of both.

Sulfite can inhibit microbes without killing them.

Sulfite does not reduce the amount of sorbate needed for stabilization, or vice versa.

Is it a chance it will make me bottle bomb without sorbate ?

Yes, there is some risk. Keep in mind that sulfite does not stop an active fermentation.

I'm looking for a TA titration kit

Do you have a pH meter? If you do, you just need a 10mL syringe and some 0.1 N NaOH.

FermCalc will do the math for any type of acid titration.

 

[doublejef]

Lea (and Jolicoeur, who just copied from Lea) both present inaccurate information. Check out the article I wrote it you want reliable info.

I read it twice but didn't see specific divergence with the books, must work on it again for sure.

Yes, there is some risk. Keep in mind that sulfite does not stop an active fermentation.

Nor does sorbate, in any case we must rack and clarify to evacuate yeast cells.
But now I get it, sorbate is when we want to backsweet and be sure yeast won't grew up later on.

Do you have a pH meter? If you do, you just need a 10mL syringe and some 0.1 N NaOH.
FermCalc will do the math for any type of acid titration.

Until now I have nothing but paper strip but I will invest soon. Another great info, thanks again.

 

[RPh_Guy]

I read it twice but didn't see specific divergence with the books, must work on it again for sure.

The main thing is this:

Jolicoeur says "After a day, half or more of the initial SO2 [added to the must] is already in the bound state". This isn't true; there's not that much in apple juice must that binds SO2. It is lost through off-gassing, oxidation, and/or microbial uptake.
His graph (figure 14.2) is completely inaccurate/misinterpreted because it's based on data from Lea about post-fermentation binding. His graph shows about double the amount of sulfite actually required. Everything else he says about sulfite dosing is based on that and therefore hugely incorrect.
He says pear juice needs more sulfite, but that's not true. He's basing that a paper from the 70s using an outdated method to measure acetaldehyde content. A newer paper using modern methods shows drastically lower acetaldehyde content in pears (around 4ppm), and thus not a significantly increased sulfite requirement.

Also there are plenty of other incorrect things about sulfite...

He says "during the fermentation [...] the free SO2 decreases slowly". That's not true. Free sulfite should be pretty much eliminated by aeration before pitching, and then any residual sulfite will decrease rapidly during fermentation by binding to fermentation byproducts (yeast increase acetaldehyde production in response to SO2).

When describing the effect of pH, he omits that it only relates to the anti-microbial activity. The anti-oxidant effect is not affected by pH.

He says small scale professional cideries don't measure sulfite level. I doubt that. I measure it; it's not that difficult.

His info about Campden tablet dosing is incorrect; 1 tab does not give 50ppm SO2 in 4.5L, at least not from any Campden tablets I can find.

He says excess sulfite taste like "sulfur or burnt matches". It doesn't.

He inserts his unscientific opinion that sulfite may cause headaches. We know scientifically that it doesn't.

I'm looking for a TA titration kit

Sorry, it's a bit difficult to look for products in another country, but a TA kit should look like this:
https://www.morebeer.com/products/cellar-science-acid-test-kit.html
It should include a basic measuring device (like a syringe), and two reagents: phenolphthalein, and 0.1N sodium hydroxide. Maybe you could buy the things separately?

I couldn't speak to the validity of that kit you linked, it seems to be using a reagent that is unfamiliar to me.

Hope this helps.

 

[doublejef]

Impressive, once again, you rule.
I'm looking to find some lab material provider that can deliver all those product.
I don't see what is phenolphthalein for in FermCalc. I guess it's to determine initial Free SO2 but I don't see how to use it?

 

[RPh_Guy]

Phenolphthalein is an indicator. It changes color when you reach the acid titration endpoint pH, which allows to visually see the pH change and know the titration is finished. You add a few drops of it at the beginning.

I use a pH meter instead of the indicator.

The TA has nothing to do with free SO2.