Sulphiting red grapes after crush

[Cellar_Rat]

I never have previously, although I am considering it this year. I usually have a very strong starter ready for immediate innoculation. How do you evenly dose 50 ppm through many cases. Does it make a difference?

[fatbloke]

I was under the impression that to get the 50ppm you add one campden tablet per liquid gallon. So I'd presume that a gallon of crushed grapes with the same amount of sulphite should do the trick.

Presume those more knowledgeable will confirm (or deny) and clarify.

regards

jtfb

[Richard S]

1 box of 20ish lb roughly = 1 gallon (ish)

[Cellar_Rat]

Would this work?
50ppm equates to 8g of pot met powder required for 54l of fresh grapes.
Which is about 10 gallons
If I dilute 8g in 100 ml of water and sprinkle 10ml over each box as they go into the crush?

Leave overnight and bring up to 25-30c and then inoculate with starter next morning?

A plan?

[lockwood1956]

Are you intending carrying out MLF on the batch?

if so 50ppm is too high, most ML cultures require sulphite levels to be under 20ppm.


Exact amount of sulphite required is determined by PH...in the absence of a ph meter then 50ppm is the baseline.

1 add 60ml 10% sulphite solution per 54 litre batch (11.89 gallons)

[NorthernWiner]

If these are your own grapes and you are inoculating immediately, why use sulphite?

I agree you should sulphite grapes that have dubious history, or that have been trucked for several days, but I see no reason whatsoever to do so for grapes that are fresh off the vine.

[goldseal]

Right ...

I'm intending to sulphite my GF grapes immediately, because they will be standing for around 36 hours before the yeast goes in.

Do I assume that whatever level of sulphite I add after crushing will still be present when I add ML bacteria many days later? Remember, I don't have a test kit.

[NorthernWiner]

Do I assume that whatever level of sulphite I add after crushing will still be present when I add ML bacteria many days later?

If you ferment in an open fermenter a lot of sulphite is lost. I measured last autumn on both red and white fermentations. What I found was that with red grapes about 30-40 ppm was lost. In fact, I had one batch of Barbera that I sulphited to 45 ppm, and it measured no sulphite at all after pressing.

Where'd it go? I assume it binds with all the oxygen introduced during punch downs, delestage, etc.

Whites fermented in carboys under airlock had about half the loss of reds.

[goldseal]

Thanks Steve. That suggests that I could add 50ppm (i.e. 1ml of 10% solution per litre, or roughly 5ml per box) initially, thereby protecting the must until I get home, but dropping to a safe level for ML after a few days.

[Cellar_Rat]

If these are your own grapes and you are inoculating immediately, why use sulphite?

I agree you should sulphite grapes that have dubious history, or that have been trucked for several days, but I see no reason whatsoever to do so for grapes that are fresh off the vine.

This has always been my approach in the past. Starter ready and going day before. Crush, improve temp to 20c immediately and then add yeast (also @20c)

If it ain't broke don't fix it ????

[NorthernWiner]

If it ain't broke don't fix it ????

Your method doesn't sound broke to me.

I shouldn't say that I never sulphite grapes fresh off the vine. Sometimes you get grapes that look pretty beat up, or have been foraged by wasps. I sometimes sulphur those just for added insurance. But if the fruit's in good shape, I don't think it's necessary.

[Cellar_Rat]

Well it has certainly never failed me.

I am a bit concerned about thwarting (triple word score?) the MLF too.

[and it has never failed me and I have at time fermented some right old rubbish !! literally !! ]

[bzac]

I sulfite about 50 ppm (reds 30 whites) (its an estimate I use 1/4 tsp kmeta per 100 lbs of grapes (reds) or 25litres of estimated finnished wine. ) at crush , the intent being to stun or kill any wild yeasts and bacteria present on the grapes . an essential step if the grapes have been through travel or storage , the grapes have any evidence of mold, or rot or damage or if you are going to do a cold soak prior to pitching your yeast. and otherwise just good safe practice.

ive also noticed my wines have a more fruit forward character compared to not adding so2 at crush .

50 ppm will be completely used up by the end of primary red ferment , punch downs and press. I've never had a post press so2 test show any free so2 on a red and never more than 5-10 ppm on a white post ferment .

so you are unlikely to have mlf issues .

with whites , its a good idea to sulfite to 30 ppm at crush to kill any wild mlb and as a hedge against must browning.

[Cellar_Rat]

Welcome to the forum!

The " fruit forward character " is something I am looking to improve. And probably the only reason (on balance) I would consider sulphiting at crush.

My concern is that my crushing is very efficient, as is my temperature correction. So from box to being inoculated with a strong started yeast is probably no more than 20 - 30 minutes?

[bzac]

selected yeasts are bread to be very sulfite tollerant , wild yeasts are not.
what sulfiting does is stun or even kill those sulfite intollerant wild yeats making it easier for your cultured yeast to get off to a good clean ferment.

there are some winemakers who like to not add sulfite so that the wild yeasts do actualy start to ferment and then the added cultured yeast will eventualy out compete them and dominate the ferment once its lag time is done.
this starting with the wild yeasts is intended to add complexity to the wine, and this can be a good thing.
but it can also add off flavours, VA & what I call "muddy fruit" notes and the stress of competition to your selected yeast . this stress can even increase the likelyhood of h2s production depending on the yeast you selected (montrachet , d47 etc...)

sulfiting can also give you some protection against the dreaded fruit fly and its bacteria . the most likely spoilage bacteria vector durring primary.

a sulfited must generally has lower VA production .

there are pros and cons to all choices in winemaking , you need to chose the ones you are most comfortable with , in either case you should always know the why and the risks of those choices.

my prefered method of adding multi yeast complexity is to divide the must into different fermenters and innoculate each of them with a different yeast and blend the wine back together at the barreling or bulk aging phase after they are dry.

Z