Maturing and storage of wine

Michael, It's probably a combination of both. You use sulfur sprays so your wine probably contains small quantities of sulfite anyway. If you want to avoid it's use be very careful when racking to avoid splashing of any kind; insert your racking drain all the way into the receiving container and let it fill gently with no splashing. Try to limit your racking to one or two before bottling. Some prefill containers or bottles with CO2 to avoid oxygenation also.

I use sulfite in small amounts. 1/8 teaspoon of pot meta per 5 gallon US is usually enough to protect a wine.

One thought might be to split your batches and sulfite one and not sulfite the other to see how it fares; you would be able to see how it affects your wife also without risking the whole batch.

Joe

Thanks for your reply Joe.One further query.I do not normally put my wine into 75cl bottles at any stage,but keep it in a gallon demijohn and put it into carafes for fairly immediate consumption during the following week.I have bottled occasionally to give wine to one of my children,but the bottling then takes place when the wine is quite young.My query now is how to keep wine in a 1 gallon demijohn nice and fresh,and perhaps I will have to use sulphites at some level.What I do not understand is why wine maturing in oak barrels for some years seems to age well without oxidation-is it to do with the large volume of wine barrels compared with my smaller but impervious glass vessels.The problem I am having does not yet seem to affect my red wines,which have higher acidity.Do you also know how much sulphite is allow for organic wine makers?Thanks again.Michael

The wine in barrels is sulfited so yuo're talking about a different situation. The larger volume does play into this in some extent because with larger containers, the airspace between the bung and wine is relatively smaller.

Red wines have tannin and other phenols that act as natural anti- oxidants, so the fact yuor red wines are faring okay is another indication that your problem is oxidation. You should really make sure whether what affects your wife are really sulfites - often people think so but the real culprit are amines in wines. Commercially dried fruit usually contains much more sulfite than wine so if she can eat it without issues, that's a good negative test.

Yeasts produce some SO2 during fermentation so no wine is free of sulfites. I don't know the number for "organic" wine makers and wouldn't really worry about it in your situation as you're not making the wine for sale. as Joe said, minimize the sulfite and rack carefully. If your wines are dry, one other thing I'd do is replace the airlock with a solid bung - airlcoks might not be airtight and in smaller containers the wine could oxidize quickly in that situation.

Pp

My wife doesn't like sulfites either so here is a link to explain the rules in the States; I'm not sure about other countries.

Oak barrels are sealed and most wine stored in them is sulfited. As to the gallon jugs, you may want o to break them up into 750 ml bottles once you tap into one, filling them completely and using T top stopper. (Tasting corks).

An old world way to minimize oxidation was to pour olive oil on top of the wine to act as a seal. That is how my grandfather did it.

Higher acid usually means lower pH; the lower the pH the less sulfite you need to protect wine; 0.8 ppm molecular is the commonly accepted value for protection. That might be why your reds keep better.

If you decide to use sulfites we can explain that in more depth or just google sulfites in this group.

Joe

Excellent advice from Joe.

The steadiness of the temperature of the stored wine is also VERY important. Temperature changes cause the wine to expand and contract. Small amounts of air get sucked through the airlock each time the wine contracts more than the 'locking volume' of the airlock. A friend of mine ruined his chardonnay by storing the airlocked carboy in his garage over the summer. The day-night temperature cycling was too much, even for his sulfited wine.

I'd definitely recommend pre-filling the racking container with CO2 (or nitrogen or argon) gas for unsulfited white wines. Even the most careful 'ungassed' racking saturates the wine with oxygen, and the only way for the wine to bind that oxygen is by oxidation (sulfite protects the wine by oxidizing much more rapidly than the wine itself; non-sulfited wines do not have this protection). The general rule of thumb for gassing a container is to flush with a minimum of three volumes of gas. This will displace about 95 percent of the air. Put the flushing hose end all the way to the bottom of the container and flush slowly (gas flow rate less than 1/2 gallon per minute). This maximizes the displacement efficiency by minimizing the gas mixing in the container. An interesting article on tank flushing with gas is at

Another easy way to accomplish vessel flushing is to use a chunk of dry ice, at a rate of at least 6 grams dry ice per liter of vessel volume (1 ounce by weight per gallon). Dry ice sublimates slowly enough to give 'laminar displacement', i.e. minimum mixing.

I'd even consider going a step further when racking unsulfited white wine, with blanketing the source container headspace while emptying; this minimizes the amount of air sucked into the emptying container. The flow rate of CO2/nitrogen/argon gas would be the same or slightly higher than the liquid emptying rate.

While some may consider these measures to be overkill, if fruity freshness of your unsulfited white wine is important, it's worth the effort.

Gene

On 20 Nov, 18:12, Joe Sallustio wrote:

Thanks for all of the replies,which have been most informative.I think that I have decided to use small additions of sulphite,since the keeping of the wine under CO2 does seem rather tricky.I also make fairly large volumes of cider(about 8% alcohol) and have had similar problems of oxidation of the cider when I try to keep it longer than one year.With the cider I will be racking off several 5 gallon fermenters during the season,and the thought of using a gas blanket during each transferance is not very appealing.I make about 120 gallons of cider and 10 gallons of wine for my family's and friends consumption.The cider is generally very good until the longest kept volumes,and I had been considering using sulphites for these last batches.I was hoping that my wine would be used for special occasions,but at the moment the cider is much better.The grape juice does seem to be of good quality,even though I am aware that the grapes are grown in the UK.I have about 30 vines,which are common European hybrids and ripen the fruit(and wood) very well.I usually pick the grapes at a Brix level about 18,and at this level the acid levels are very manageable.Some of these varieties of grape regularly win top prizes at European blind tastings,so I am confident that my grape juice is excellent.In my first year,my first attempts were very good,but the wine was drunk around May,just 8 months after harvest.Since then I have been keeping the wine longer than 12 months,and this is where the problem has arisen,and particularly for the whites.As I indicated in my earlier mail,I wash the grapes and ferment the grapes with the natural yeasts without any addition of sulphites.So I really wish to produce very good quality (I am even considering reducing grape yield in the future to improve juice quality)wine,which retains its fresh and fruity characteristics until drunk.The climate in southern England is variable from one year to the next,although climate change is giving us higher temperatures than 30 years ago,and it is necessary to store wine(and cider ) for more than a year to cope with this.So I think that I will add up to 50 ppm of sulphite (10g/100ml gives a 5% solution and 5ml/gallon of wine gives

50ppm ?)using sodium metabisulphite,but I am still not clear when to add this.As I understand it,the primary fermentation takes 4-6 weeks,and the secondary malolactic fermentation about twice as long.I read that sulphite in the wine at some level inhibits malolactic fermentation,which could be a disadvantage for me since in a cool season when the juice is more acidic,this secondary fermentation is valuable in reducing acidity.Malolactic fermentation needs a higher temperature to get started,and my storage area is typically 45-50F until the April/May .So there is a conflict in waiting too long for the secondary fermentation to be completed,such that oxidation sets in.I am therefore thinking of adding 50ppm sulphite to my wines (and cider) around the end of April,which is about 6 months after harvest.I hope that my understanding is beginning to get up to speed,but I would very much welcome further comments about whether what I am suggesting really will maintain the quality of my juice.Thanks again,Michael

First a question - are you sure your wines go through ML fermentation? The bacteria don't like low pH, and it sounds like your pH might be pretty low, given you pick your grapes at 18B - any chance you could let them hang longer to get higher sugar?

For sulfite additions calculation, I'd recommend one of the online calculators, for ex.:

Your number looks too high based on the data that you get there.

Otherwise yes, the sulfite goes in after MLF if you're doing that.

Pp

Hi again,Joe.I appreciate all of your comments.I am not sure whether my wines go through a malolactic fermentation.The only observation I make is that I do get a precipitate of white crystals when the wine is about 4-5 months from harvest,and,maybe incorrectly assumed that this was a sign of secondary fermentation.What I do know is that my white wines are very well balanced for drinking around May,with no indication of too much acidity.It is very difficult to get very high sugars in our UK environment and a Brix reading of 18 is regarded as good.It can be dangerous to leave the wines too late into October as a short period of rain then tends to split the grapes and botrytis gets in quickly.I do not spray for botrytis at all and it is an ever present threat at harvest time.The other problem I have is that my cider orchard and vines are at our cottage in Herefordshire which is

120 miles away from our main home in Manchester.I am now retired from my job as research physicist at The University of Manchester,so am beginning to spend more time at the cottage.However in the busy cider making and grape harvest season (September-early November) I am not usually away for more than 10 days-but it does mean I may have to pick when the sugar level is not quite the highest,and this means somewhere between 17-19.I have recently changed some of my vine varieties to include some that are more resistant to botrytis,so that I can possibly leave the grapes longer before harvest.So my main concern,particularly with the whites,is how to preserve the fresh fruity quality for up to 2 years,rather than 6 months.I am aware that some winemakers put sulphite in to the must right from the start,which could protect the wine through the fermentation,racking and bottling process,but I would rather just include it to lengthen the storage time with a minimum amount.So the question is,when to add the sulphite?-first racking or after a possible(?)malolactic fermentation- and whether to use 30ppm or 50ppm generally for reds and whites or perhaps just for the whites as the reds seem to last considerably longer.Thanks,again,Michael

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Hi again,I had a look at the sulphite table,which is for potassium metabisulphite.My numbers were for sodium metabisulphite and for 50ppm correspond to 2.5g of sodium metabisulphite/5 gallons.In your table using the potassium salt,50 ppm corresponds to 1.64g of potassium metabisulphite.It seems to me that maybe you should need a higher mass of potassium salt to get the equivalent amount of sulphite to the light sodium salt,but maybe my chemistry is failing me.So you could be right and my numbers for sodium are too high.I will investigate further! Cheers,Michael

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Hi again,My replies seem difficult to access at the moment but they are there,Forget about my last comments concerning the relation between sodium and potassium metabisulfite.I misread the table you referred to.I have looked up a couple more web sites and I am now happy that they are consistent and that my sodium numbers do correspond to 50ppm,Cheers again Michael

Michael:

The formsoft online sulfite table generator can be set tp either sodium or potassium. You do need more potassium based powder than sodium, that's correct. However, I do believe that 2.5g of either is too high to give you 50 ppm of SO2 in your wine. Here's another link - an in depth explanation of sulfites in wine - which should cover all your questions in detail:

under Articles -> Sulphur Dioxide

In section 19, there is a couple of sample calculations - they're for potasium meta but you can adjust them for sodium meta by using the

67.4 factor instead of 57.6. I did the 2nd calculation for your numbers and it gives the same result as the table - 14.04 ml of the stock solution for 5 US gallons (if you use imperial gallons, just recalucate for 6 US gals).

Otherwise, sulfite added to the must before fermentation will be pretty much gone after the ferment, so it won't protect your wine for long term aging. You need to make the sulfite addition after the ferment (or ML ferment if you go that route).

White crystals in the carboy sounds like "wine diamonds", i.e., tartaric acid precipitating out as cream of tartar - normal occurrence for high acid wines. From what you're saying, I doubt your wines go through ML but you can always make sure by doing a chromatography test. Otherwise, just way until the wines taste the way you like them and sulfite then - but don't wait with that too long, the April date you mentioned is about as far as you can stretch it. But I would recommend making sure about the ML - because if your wines are not going through it, you can and should sulfite right after the ferment is over, during the first racking.

Pp

Thanks again,Joe.I think that we are almost there.I will check again on the sulphite numbers,and also try to see whether I really do get an ML fermentation.You mentioned a chromatography test-can you buy simple kits for this?Alternatively,I could taste the wine around Christmas time-and maybe drink some-and if I like it,add some sulphite then as you are suggesting.I think that the whites are pretty good early,so this procedure maybe quite good,provided I do not compromise the wine by continually unstoppering it to taste!I am sure that if I pick the white grapes at about 18 Brix,then the quality should be excellent.With the reds,I believe that I can leave them longer,as I do not seem to have a problem with oxidation so far.(I mean here longer in the glass carboy before sulphiting).Incidentally,does it matter,with regards to oxidation,whether I close the 1 gallon demijohn with an airlock or with a straight rubber bung or a cork bung.With these demijohns,being vertical,a cork bung would not be moistened as in horizontal bottle storage,so probably a rubber bung is better.However,I have noticed that with my cider making rubber bungs can go loose at times if there is any excess pressure left-is it wise to use potassium sorbate if sulphiting early,though I am reluctant to use even more chemicals,since I am trying to produce a reasonably organic wine-whatever that really means.Best regards,Michael

Hi again,Thanks for the web site you included which gives extremely good coverage of the use of sulphites in wine.I will read it carefully soon to extend my knowledge into this area of wine chemistry.For the moment I think your comments are correct and that I have been adding sodium met to give nearer 70ppmSO2 than 50ppmSO2.I obtained my original numbers from a pretty good cider web site,so I will have a look at them again.Michael

Yes, you can buy simple ML kits, at least here in North America, not sure about Europe. Or, given your background, you could probably assemble one yourself - the only tricky part is mixing the solvent. There is also a paper-strip instant test produced by somebody - Accuvin?

Solid bung will give a better seal, but the wine HAS to be stable and you should also watch outside temperature fluctuations. It's not much fun coming back home in summer after an evening soccer game and finding one's flour covered in 6 gals of blueberry port - the wine was stable but the carboy cracked because of increased pressure caused by summer heat.

Pp

Thanks,Joe.I am wary of temperature fluctuations as I keep my wine in our garage.I try to keep sufficient gap at the top of the 1 gallon demijohns so that the expanded liquid doesnt force the rubber bung out in warm summer weather.With my cider making,on several occasions the rubber bungs have been forced out since the cider was put in when the cider was not fully fermented out.I am pretty sure that the bungs would come out of the demijohn rather than crack it,but maybe this is not always the case.Your 6 gallon carboy which cracked was maybe more vulnerable and liable to crack at lower pressure than with a smaller diameter 1 gallon demijohn?I am also aware of downward fluctuations in temperature,and this is one of the reasons why I was asking you whether airlocks or bungs are to be preferred-I have noticed on some occasions that when the temperature drops below zero(outside!)the airlock goes into a negative pressure state and could pull air in.I suppose temperature fluctuations for England are probably not as serious as those where you are in the U.S.Our summers are getting warmer,but temperatures rarely get above 30C,or below -5C,and then not for long.

I am reading a book at the moment about a modern French winemaker.It is the form of a novel but describes his winemaking year in reasonable detail.He seems to put great emphasis of getting his grapes harvested and pressed very quickly to avoid oxidation,and retain the fresh fruity flavours at all stages.He is an organic wine maker,and is experimenting to see what the minimum of sulphite needs to be added at the two important stages.That is,initially when the grapes are pressed and just before the wine is bottled.Unfortunately,he does not give the quantities!!I hope to follow this kind of practise,and may probably add 20ppm initially and 30ppm before putting into the demijohns for longer storage.I may vary this for high or low acid juices(early or late harvesting),but wish to keep it simple.In your experience,does

20ppm or so initially inhibit the natural fermentation significantly,and is it enough to do any good at all?

Thanks again for your help,Michael

Hi. It may be a little late this year unless you're conducting spontaneous/natural malolactic ferfmentation. I'm with Accuvin. We do make rapid strip tests for L-Lactic Acid (to check that MLF has started) and for Malic Acid (to verify MLF completion). They are more sensitive than chromatography, take only 4 minutes, and don't require any other lab equipment. They might make your MLF monitoring easier. Regards

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