Why sanitize equipment with so many germs on the uncooked fruit?

[Just Sara]

Don't get me wrong, I hate germs and love sanitizing everything, but it seems kind of pointless if I'm then using raw fruit that's been outdoors for months, birds and animals and the wind itself depositing all kinds of wee friends on it. Is the sanitizing of equipment to just cut down on the amount of bacteria/yeast, or... ?

 

[bernardsmith]

Welcome aboard, Just Sara. An interesting question. My understanding is that most wine makers sanitize their equipment AND work to kill or inhibit the growth of all bacteria and mold and yeast on their fruit using the same compound (K-Meta ) but at a higher concentration of SO2 to sanitize equipment and a lower concentration to kill the indigenous yeast. The problem that sanitization deals with is that your wine will be in contact with carboys and bungs and the like not for a few minutes but for months and months and sugars in the fruit and moisture are a feast for bacteria that will compete with the yeast and will add flavors that will likely spoil your wines. Moreover, during the first few days of fermentation, the yeast may not have developed a large enough colony to overrun spoilage bacteria and mold that simple cleaning may not remove: for example, your water source may be clean enough for you to drink but it may nevertheless harbor bacteria. Soap is not really an option as soap leaves a film which for dishes and the like may not be a problem but , again, given the very long periods of time wine is in fermenters and bottles, that film in contact with a solvent such as alcohol with the acidity associated with wine (a pH of about 3.0) is enough to detach that film into the wine. Note, that this same alcohol and acidity means that the likelihood of any pathogenic bacteria developing is zero but there are hundreds of strains of yeast and indeed bacteria, (The secondary MLF fermentation of red wine is done with bacteria and not yeast) only a few which we view as producing spoilage that we enjoy.

 

[Just Sara]

Thanks for the welcome, and for the answer! I'm glad to hear that the metabisulfites handle bacteria too, whew. I feel a little better about it all now. And I mean, I can see all over these boards that whatever people are doing is usually working, so I'll go ahead and just do as instructed, but it still makes me think twice when I start to worry about heavily StarSan-ing a spoon when any potential problems with bacteria will almost certainly have come from my uncooked, lightly treated fruit I'm now stirring with that very clean spoon. I've lacto-fermented bell peppers and stuff before, and all the bacteria you need to do it is already on those fruits or veggies that had been hanging out outdoors (even if they'd been misted with chlorinated water at the grocery store).

A little side note: I was slightly germophobic in my late teens after I took my first food-handlers card class and realized my Mom was touching our wooden sink handles with raw chicken on her hands and I've never really recovered, ha ha! I also worked in a nursing home with a ventilator unit for a decade and germs were a big part of my life; ever since lockdown I've needed to think WAY more about germs than I ever thought I would, and working in healthcare during a pandemic WILL change your life. So because of all my education and training, I have this (not always logical) germ awareness that I can usually switch on and off, it's hard to explain, but I let it get stuck in the "on" position for like 2 years during the pandemic. I try to use my germ awareness for the powers of good, when I can, like when asking wine sanitization questions!

I'll eat an apple off the ground at the park any day, but touch that public door handle?? MUST HAND SANITIZE!! Honestly, I'm only wary of germs on/in humans and animals, and improperly home-canned food. The rest of the world is mostly fine.

 

[bernardsmith]

In NYS you cannot buy commercially pressed apple juice unless the seller has pasteurized the juice because any apples that had fallen from the trees on to the ground and were added to the fruit to be pressed were viewed as potentially loaded with e-coli and listeria from passing animals. For hard cider, you want to use those orchards that use UV pasteurization but that, as they say, is another story. Me? I would wash any apples that you pick up from the ground in a park.

 

[pvtpublic]

It is to cut down on the bacterial load on the must, especially the nasties. However, the fruit should be washed a bit, but not scrubbed. Most everything is covered in yeast. You can actually see it on certain fruits, like plums, grapes, and juniper berries (not actually a fruit, I know). It's that powdery white film on the outside that you can wipe off. If you're going to let your must wild ferment, you'll want that white film intact and it will provide some good bacteria in there to build more character. If you don't want to go this route, I suggest freezing the fruit in deep freeze for two weeks, to kill anything that can't handle those temps and then stewing them at a pasteurization temp for 20 minutes with a lid on. Don't boil it or take the lid off, you want to retain the flavors and aromas as much as possible. Let it cool to pitch temps with the cover on and add pectic enzyme with the yeast.

Edit: I forgot to mention metabisulfite in the raw version, let it sit 24-48 before you pitch

 

[PaulyWally]

If you're going to let your must wild ferment, you'll want that white film intact and it will provide some good bacteria in there to build more character.

+1

A guy that operates a winery near me will allow the wild yeast to do the fermentation in his red wines... as long is it activates. I've been drinking his wines for years and can tell the difference. The batches he adds yeast to are a bit more sharp, acidic, and require more time to age before they get rich and mellow. The batches that he doesn't add yeast to are more earthy and complex - lots of stuff happening on the palette - and they are more palatable when they are young (although the flavors deepen even more with age).

That said, part of it could be the yeast strain he uses for his reds. I'm still quite a novice in wine-making and don't yet have a grasp on what different strains do for the final product.

 

[Bobby_M]

If you don't want to go this route, I suggest freezing the fruit in deep freeze for two weeks, to kill anything that can't handle those temps....

Freezing doesn't really do much to bacteria other than stop growth until you want to use the fruit but I do think freezing and thawing soft fruits make them turn to liquid quickly so that metabisulfite and pectic enzymes can work faster.

I'll eat an apple off the ground at the park any day, but touch that public door handle?? MUST HAND SANITIZE!! Honestly, I'm only wary of germs on/in humans and animals, and improperly home-canned food. The rest of the world is mostly fine.

Eating things with most common bacteria is usually fine because out stomachs dispatch it quickly (though E. coli and salmonella are pretty nasty). The issue at hand is leaving all those surface organisms in contact with a perfect growth medium at near optimum growth temperatures for the amount of time it takes desirable yeasts to grow to a large enough colony to ferment.

The primary pitfall to allowing wild fermentation is ending up with an imbalance of organisms. A small colony of yeast vs. a large colony of bacteria usually doesn't work out too well. Some orchards just have more desirable flora than others and of course, weather plays a role and varies every harvest year.

Hitting all pressed/juiced fruits with Metabisulfites (and I also use pectic enzyme) 2 days prior to pitching a healthy quantity of specific yeast just widens your odds of successful fermentation. I'm not suggesting that extremely good products can't be made with wild ferments, but they don't all go great. I have a lot of locals that bring me their wines and ask how to fix them and I have to spit the vial stuff out because of how south they can go.

 

[pvtpublic]

Freezing doesn't really do much to bacteria other than stop growth until you want to use the fruit but I do think freezing and thawing soft fruits make them turn to liquid quickly so that metabisulfite and pectic enzymes can work faster.

If you put it into your fridge freezer, yes. But putting into a chest freezer that gets down to at least 0F for 2 weeks will start to kill off a few of them. It helps reduce the yeast's competition, if only just a little bit. The breaking down of the cell walls is the primary reason to freeze them though, you're absolutely right.

Eating things with most common bacteria is usually fine because out stomachs dispatch it quickly (though E. coli and salmonella are pretty nasty). The issue at hand is leaving all those surface organisms in contact with a perfect growth medium at near optimum growth temperatures for the amount of time it takes desirable yeasts to grow to a large enough colony to ferment.

The primary pitfall to allowing wild fermentation is ending up with an imbalance of organisms. A small colony of yeast vs. a large colony of bacteria usually doesn't work out too well. Some orchards just have more desirable flora than others and of course, weather plays a role and varies every harvest year.

Hitting all pressed/juiced fruits with Metabisulfites (and I also use pectic enzyme) 2 days prior to pitching a healthy quantity of specific yeast just widens your odds of successful fermentation. I'm not suggesting that extremely good products can't be made with wild ferments, but they don't all go great. I have a lot of locals that bring me their wines and ask how to fix them and I have to spit the vial stuff out because of how south they can go.

This is great info.

 

[MilesBFree]

On some fruit and dandelion petals I have boiled them. Freezing breaks down the fruit and boiling helps that a bit more too. Also kills most of the bugs.

I am with you on dirt - we have a couple of apple trees and herb garden and have no reservations on eating things right off the plant or ground. But touch a door handle and I feel like I should hold my hand as far away from the rest of my body as possible. And I do the hovering thing in public restrooms

But I digress... K-meta will kill the wild yeast and bacteria. Unless the fruit is truly bad it shouldn't contribute bad bacteria to any real extent.

(Note: edited since i had bad info on K-meta not killing bacteria. Thanks for pointing that out, everyone.)

 

[Just Sara]

On some fruit and dandelion petals I have boiled them. Freezing breaks down the fruit and boiling helps that a bit more too. Also kills most of the bugs.

I am with you on dirt - we have a couple of apple trees and herb garden and have no reservations on eating things right off the plant or ground. But touch a door handle and I feel like I should hold my hand as far away from the rest of my body as possible. And I do the hovering thing in public restrooms

But I digress... K-meta will kill the wild yeast but not bacteria. Unless the fruit is truly bad it shouldn't contribute bad bacteria to any real extent.

Seat covers, gotta love ‘em!

 

[Bobby_M]

... K-meta will kill the wild yeast but not bacteria.

Do you have any academic references to support this statement? I don't have any to the contrary either, but I've always understood it to be effective at killing yeast, gram-positive bacteria, and mold spores.

 

[bernardsmith]

K-meta produces Sulfur dioxide. That's a powerful bactericide. (sulfa was /is used as an antibiotic, tho' I am not certain that those earlier antibiotics contained sulfur per se
).

 

[tracer bullet]

https://www.researchgate.net/figure...-measured-as-OD-600-Results-of_fig3_320481298
For the chart, the X axis is the concentration of K-Meta, the Y axis is the density of the bacteria. Each chart represents a bacteria. Each colored line is how long a sample sat out and was allowed to multiply prior to the K-Meta at each concentration being applied to it. The take-away is that there is a point (somethign like 500PPM but it varies one bacteria to another, and certainly under 1000), K-Meta effectively does kill the bacteria.

 

[Just Sara]

This is all getting really informative, it was exactly what I was hoping you guys would help me out with, thank you SO much. I can't believe y'all citing your sources, this is making my day.