I've been able to acquire wine grapes from a few local wineries. Once I've crushed the grapes, is it necessary to add chemicals (such as campden tablets) to the must to sanitize the grapes or would it be good enough just to ensure all my equipment are sanitized?
Necessary to add chemicals to must to sanitize?
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You'll get some varying views on this topic, happy to share mine. If the fruit is in good shape, and MLF is planned for the wine, skip it. If the fruit is not so hot and MLF is planned, a light dose would be in order. If the fruit is great or not so hot and you don't plan to MLF, no harm in dosing.
NorCal
Senior Member
I agree with John, less is more with winemaking. The reason you add SO2 to the must is to kill bacteria and wild yeast. If there is excellent fruit, it reduces the requirement, bad fruit it increases the need. When in doubt, I add.
I don't consider campden tabs as chemicals but yeah I would use them, again personal preference but I like to make sure that everything goes well and that nothing funky grows in my crushed grapes.
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Depending on where the grapes come from, I might not add anything to them at crush. I have done successful native yeast ferments a few times. But for those, the grapes are in great shape, came from known vineyards that I have had wines from and talked with the winemakers and often the vineyard managers. If I were picking up grapes from a commercial place, I would always add kmeta, pretty much at the same levels as John above. Other fruits always get a good dose of kmeta and I don't do mlf on them.
balatonwine
The Verecund Vigneron
They are absolutely chemicals - potassium or sodium metabisulfite.
Not only that, but they are reactive chemicals that interact with the must to produce sulfur dioxide (SO2).
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JohnD, what to you consider a light dose of Kmeta added to the must? Say blank per gallon or Lug. Our grapes arrive Sunday, Thanks. Roy
My goal would be to keep the dose at 1/2 or less of the mlb tolerance. So a little shot like 20 ppm could accomplish that and not provide too much deterrent for mlb down the road.
The grapes will come from local wineries in Paso Robles, CA, I can check with the winemakers as well. I'm assuming then if I don't add anything, I wouldn't need to add any wine yeast?
Ajmassa
just a guy
Technically. But that’s not the mindset here. Skipping So2 at crush is to benefit the MLf. Adding your own selected commercial yeast is part of the fun!
And even if you added a small dose of So2 the wild yeast would still take over if ya waited Long enough. The addition is killing the bacteria. But just stunning wild yeast.
I’d be more inclined to dose healthy grapes if I had some serious acid adjusting to do. Knowing it could be another day or 2 before pitching yeast.
Also, nobody has mentioned yet that home winemakeing grapes are typically treated with sulphites somewhere along the line before its in our house. Not high ppms, but enough to comfortably skip adding some under the right circumstances.
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Masbustelo
Junior Member
To answer your question about yeast being present on the grapes. More than likely yes.
Natural fermentation is a misnomer. Yeast grows on the grape skins, so "natural fermentation" is allowing that yeast (could be plural) to go. ALL fermentation is natural. 
I am risk adverse, so I add a commercial yeast. If I purchased from a vineyard where I know the wild yeast produces good results, I would try it once. But without that assurance? As I said, I'm risk adverse.
In another thread it was mentioned that vineyards can innoculate with a specific strain of yeast, so that strain is what is growing on the yeast. If I had a vineyard, that's what I would do. Although I'd probably innoculate each batch with the same strain ....
I am risk adverse, so I add a commercial yeast. If I purchased from a vineyard where I know the wild yeast produces good results, I would try it once. But without that assurance? As I said, I'm risk adverse.
In another thread it was mentioned that vineyards can innoculate with a specific strain of yeast, so that strain is what is growing on the yeast. If I had a vineyard, that's what I would do. Although I'd probably innoculate each batch with the same strain ....
balatonwine
The Verecund Vigneron
Natural fermentation is a misnomer. Yeast grows on the grape skins, so "natural fermentation" is allowing that yeast (could be plural) to go. ALL fermentation is natural.
Fundamentally, I agree with you.
But.....
It is a matter of definition. What some people think of as "natural" is to them as defined as simply there was no commercial yeast package "added" to the must. That is, the term "natural" does not have the same legal status like "organic", and anyone can define it as they wish, for marketing purposes or whatever.
But....
Actually, a lot of such "natural" fermentation does not necessarily come from yeast on the grapes in established wineries, but yeast selected for, and over time, has become concentrated in the winery with yeast that completes the fermentation. Maybe that feral yeast colony started from a commercial package yeast a decade or more ago (so more "feral" than "natural"). And these yeast are everywhere -- on the walls, floor, cracks, air etc. Thus a lot of "natural" fermentation comes from such feral yeast in the winery, not necessarily from the grapes alone. Which of course begs the question -- is a "winery", which is a human structure, really a "natural" source of yeast?
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True.
I'm trying to get people to think this idea through, to consider the reality of fermentation and what terms like "natural" really mean. Knowledge let's people make their own informed decisions. You did a great job in expanding my point, identifying things I didn't consider.
The idea that regardless of what gets innoculated with what, the yeast growing in an area can be something totally different? I use EC-1118 for at least half of my wines ... so it's entirely possible that is resident in my cellar. If so, that's a good thing (as opposed to completely unwanted yeast and bacteria). But without knowing ... I tear open and sprinkle that little packet on each batch ....
LOL!Which of course begs the question -- is a "winery", which is a human structure, really a "natural" source of yeast?
Ajmassa
just a guy
Always an interesting topic. But can also just complicate something that doesn’t need to be complicated. The “natural” or “wild”’or “native” yeast references can lead down the rabbit hole. Unless ya want to through it, otherwise just confusing things.
“Natural” ferment to me = not adding commercial yeast. That’s it.
You can niggle it to death. But in the end— I’ll never know where the wild yeast is actually coming from-that’s true for most of us (all?). Staying out of that hole.
balatonwine
The Verecund Vigneron
Good for you. I do the same.
I once commented (at another site) that due to some insects getting squished into many wines (except those hand sorted by grape, or via other special manual or technical processing), was it really possible to call wines not so specially processed "vegan". Since even insects are also part of the animal kingdom.
Wow. Never had such a long list of hateful comments toward any post I have made before or since. No interest in discussing, contemplating or philosophical discourse on the topic. Just a lot of hate.... Discussing politics seemed safer.....
PJ805, I’m jealous as hell. My local Paso winery looks more like an 18 wheeler than a winery. You have options and asking the winemaker what he does is probably best.
I’m on the east coast, my grapes have been in coolers for at least a week or two (maybe more depending on how varied my purchase is). My grapes arrive at about 36F. I add 50ppm SO2 at crush regardless. Unless I intervene with heat, my grapes cold soak for about two days before my must gets above 60F where I can pitch. I have no problem with the yeast starting because by then the SO2 has disapated. I like the protection it affords during my forced cold soak. I do rehydrate my yeast and feed it with must until the temperatures equal before I pitch. I also add some heat to get it from 60F to 65F+. From there it takes off.
I would not worry about adding SO2 preferment affecting MLF. It’s been gassed in the coolers and by the time fermentation has ended, SO2 is barely measurable. I use commercial MLB, most of which have a moderate SO2 tolerance. Other than rehydrating with acti-ml so I can divide between my batches, I add nothing. Never had an issue.
Way past what you asked.
I’m on the east coast, my grapes have been in coolers for at least a week or two (maybe more depending on how varied my purchase is). My grapes arrive at about 36F. I add 50ppm SO2 at crush regardless. Unless I intervene with heat, my grapes cold soak for about two days before my must gets above 60F where I can pitch. I have no problem with the yeast starting because by then the SO2 has disapated. I like the protection it affords during my forced cold soak. I do rehydrate my yeast and feed it with must until the temperatures equal before I pitch. I also add some heat to get it from 60F to 65F+. From there it takes off.
I would not worry about adding SO2 preferment affecting MLF. It’s been gassed in the coolers and by the time fermentation has ended, SO2 is barely measurable. I use commercial MLB, most of which have a moderate SO2 tolerance. Other than rehydrating with acti-ml so I can divide between my batches, I add nothing. Never had an issue.
Way past what you asked.
Ajmassa
just a guy
***edit
In hindsight my last reply was unnecessarily confrontational. Decided to just remove it. Though I would still NEVER classify those replies as ‘hateful’. Balatonwine you’ve got a special skill in eliciting reactions . The reference to accidental bugs in must causing a wine to not be vegan is a perfect example of how it’s done too.
In hindsight my last reply was unnecessarily confrontational. Decided to just remove it. Though I would still NEVER classify those replies as ‘hateful’. Balatonwine you’ve got a special skill in eliciting reactions . The reference to accidental bugs in must causing a wine to not be vegan is a perfect example of how it’s done too.
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I’ll just stick with “native” yeast being the yeast that comes on your grapes or lives in your production area, and “cultured” yeast being those that I buy in a package and sprinkle on top.
