yeast starter

[thesnow]

Hi all, i make wine from grapes.
I usually remove some must to be used with the yeast starter at the beginning before adding the potassium sulifte to kill the bad bacterica in the primary.
Question is.. does it matter to take the must before you add the potassium sulifite or after. Or do I wait 12hrs later for the must that had the potassium sulfite to kill the bad bacteria off. Problem waiting is that the clock is ticking..

 

[bob1]

you are doing just fine.

 

[thesnow]

OK, so I will continue taking out the must needed for my yeast starter; before I add the potassium meta sulfite to the primary. Another thing that's been bothering me. When I add the potassium meta sulfite to the primary to kill off the bad yeast or bacteria. Do I really need to wait 12hr to 24hrs before i add my yeast starter to the primary.

 

[bob1]

yes, Things in the back of the head but if I remember right it needs time to bond I think, if you start a fermentation to early it all gets blown off.

 

[JohnT]

I agree, You really do need to wait. I normally wait 24 hours before pitching yeast.

The only flaw I see is that you are hitting the primary with k-meta to kill wild yeasts and potentially bad bacteria. By taking some must out first, making a starter out of it, then reintroducing the starter back into your primary, you could be (potentially) re-introducing the wild yeast and bacteria back into your must (only this time more active, but in smaller amounts).

I would suggest that you make your starter from something more sterile or simply add the yeast in dry (once you have waited 24 hours).

johnT.

 

[thesnow]

Thank you , much appreciated

 

[MalvinaScordaad]

The amount of bacteria and or wild yeast introduced by the starter is insignificant. Actually a properly made starter will have killed off the wild yeast. Using Must to make a starter and not using sulfited Must to do it is a good practice as it will enable a quicker yeast colony reproduction. Making a starter also enables the yeast to acclimate to the environment and develop proper cell walls for later when the alcohol environment threatens their health. Thus by doing this you are ensuring a fermentation that will leave no residual sugar which if present can lead to VA production during MLF. If you have your Must temps in the 80s when building the culture you should find a 12 hours more than a sufficient time to pitch. The key is to keep the Culture within 10 degrees of the Must so as not to shock the yeast.
If you do not follow this procedure and let your Must sit around above 50 degrees the time you wait for the sprinkled yeast to actually begin a fermentation and create a cap will give your Must more than enough time to grow bacteria and allow wild yeast to get a foothold even if the Must has been sulfited. There is no upside to that even if the yeast you are using has a killer factor.
Malvina

One other thing to be clear you said "Do I really need to wait 12hr to 24hrs before i add my yeast starter to the primary. " You are waiting for the culture to develop 12 hours not waiting for the Must to do anything. If anything the Must would benefit from the quickest start possible unless you are holding the temp under 45 degrees doing a cold soak.

 

[JohnT]

Malvina,

I agree/disagree with you on some of these points.

The time you wait is to allow for the k-meta to dissapate. You would not be able to add yeast immediatly after adding the k-meta. The result would be dead yeast.

I think that thesnow was talking about simply adding yeast to a sample of must to create a starter. This would be unsterilized must. Anything in that starter (wild yeast or bacteria) would be growing and multiplying during fermentation alongside your cultured yeast. I did not say that this is an automatic, but should certainly be a concern.

(just my opinion)

johnT.

 

[MalvinaScordaad]

Well John I certainly disagree with you on a number of fronts. There is no time needed to dissipate SO2 if you are able to start your fermentation quickly. In fact with healthy grapes there is no need for an initial dose of K meta in the first place. If grapes are in excellent condition you can skip the addition without problem. The idea is to get your cap which protects the Must with Co2 as quick as possible. Building a large strong culture allows that to happen sooner rather than later. You are not sterilizing the Must with the addition of S02 at best you are simply stunning the natural yeast. You are not killing bacteria either. You also seem to think that the wild yeast will grow alongside the cultured yeast. The natural yeast are so weak they can't compete and die at the end of Lag Phase and furthermore a Cultured Yeast with a killer factor will see to their demise completely. Using your method of sprinkling yeast on the Must and not building the culture should be more of a concern to you than non sulphited must used to build a culture. Using your method you are waiting in excess of 48 - 72 hours for a Cap you are giving much more of a time frame for bacterial growth and increased wild yeast production to form. Secondly your yeast colony has never had the opportunity to develop properly for the rigors of early and later stages of fermentation risking a stuck fermentation or residual sugar. A much bigger concern in my mind.
Malvina

 

[bob1]

so I know SO2 does not kill the yeast but I did think it killed things like mold and bacteria. Are you saying it doesn't.

 

[MalvinaScordaad]

So2 can help slow and control a population of natural yeast, bacteria and slight mold growth at the typical levels of So2 usually added, however you are kidding yourself if you think it will do much more. If you have seriously molded grapes that are in bad condition the K Meta additions are enormous compared to the 25 ppm that is usually added as a matter of course. If added in that amount you then have to try for a very hot ferment to blow off as much as possible so you can get a MLF done. Many times wine made from grapes in that condition are blended after pressing prior to MLF if the So2 levels are still too high after fermentation.

I will say there are 2 schools of thought on adding So2. Some do it as a matter of practice, others only when grapes are not in the perfect condition. Some Winemakers believe that the wines taste fresher when So2 is added prior to fermentation. They could be right if dealing with Whites but I do not believe it is due to stalling natural yeast or stunning bacteria. White Juice is very easily oxidized and a dose of So2 does afford protection from oxidation that can lead to a fresher tasting white.

Malvina

 

[bob1]

it does not kill yeast unless you use way to much. But I I did think that it was said it killed bacteria but then again I might be misunderstanding the explanation of sulfite. I pulled this off of goggle " This both prevents most wild microorganisms from growing, and it acts as a potent antioxidant, protecting both the color and delicate flavors of wine." Notice it does not say it kills them.

 

[JohnT]

BOB1,

I found the following ..

Wine maker's toy store...

Free sulfites come in the form of sulfurous acid, H2 SO3, or "molecular sulfite." It is this sulfite that has the ability to cross cell walls and destroy unwanted bacteria or bind with oxygen to prevent oxidation of the wine. If your grapes are infected with Botrytis, free sulfite can bind with gluconic acid to minimize its effects.

another site..
Winemakers don't add k-meta to stop fermentation before the wine is dry. K-meta is not strong enough to do this. Winemakers use potassium sorbate to do this. K-meta does prevent oxidation. It preservative qualities lie in its ability to stop other bacteria & wild yeast from ramping up and spoiling the wine. At the levels used (25-50 ppm), it's not strong enough to stop a runaway wine yeast train.

Wikipedia..
Potassium metabisulfite is a common wine or must additive, in which it forms sulfur dioxide gas (SO2). This both prevents most wild microorganisms from growing, and it acts as a potent antioxidant, protecting both the color and delicate flavors of wine.
The typical dosage is 1/4 tsp (1.2322304 milliliters) potassium metabisulfite per six-gallon bucket of must (yielding roughly 75 ppm of SO2) prior to fermentation; then 1/2 tsp per six-gallon bucket (150 ppm of SO2) at bottling. Most commercial wineries do not add more than 30ppm at bottling.
Winemaking equipment is sanitized by spraying with a 1% SO2 (2 tsp potassium metabisulfite per L) solution.



So, some think that it can kill bacteria, some do not. all agree that it does prevent the growth of bacteria and yeast, but will not nessarilly kill yeast.

Now I am confused. I have been using k-meta for 22 years! Why should I rinse my equipment in k-meta and not just plain water?



Malvina,

Thanks for correcting me.

I need to do a little re-thinking on some aspects of my process. I have never had a stuck fermentation, trouble getting fermentation to begin, and all of my wines have fermented to dry. This is not to say that I was not always at risk.

What would your recipe be for a yeast culture for 100 liters of wine?

 

[MalvinaScordaad]

Now I am confused. I have been using k-meta for 22 years! Why should I rinse my equipment in k-meta and not just plain water?



Malvina,

Thanks for correcting me.

I need to do a little re-thinking on some aspects of my process. I have never had a stuck fermentation, trouble getting fermentation to begin, and all of my wines have fermented to dry. This is not to say that I was not always at risk.

What would your recipe be for a yeast culture for 100 liters of wine?

John your solution of KMeta for sanitizing is 500 ppm or better and at that level in kills just about everything.

25 grams of yeast, 30 grams of go ferm built up slowly to about 3 gallons over 12 hours not exceeding 10 degree temperature changes when adding to the culture or finally when pitching in the must.
Malvina

 

[bob1]

We just posted on another forum about this also. The rinsing that is. I and another fellow here have been to the commercial wineries and thats all I saw them do is just rinse everything well with water. A lot of people still just sanitize equipment with bleach water. I did that for years with no problem.

 

[JohnT]

John your solution of KMeta for sanitizing is 500 ppm or better and at that level in kills just about everything.

25 grams of yeast, 30 grams of go ferm built up slowly to about 3 gallons over 12 hours not exceeding 10 degree temperature changes when adding to the culture or finally when pitching in the must.
Malvina

So, If I understand you, K-meta will destroy bacteria and yeast, provided it is at the right concentration and the isse with k-meta in wine is that, at 30 to 60ppm, the concentration is not enough to kill anything?

 

[bob1]

"

molecular sulfite." It is this sulfite that has the ability to cross cell walls and destroy unwanted bacteria or bind with oxygen to prevent oxidation of the wine.

I think there may be some truth to the fact that it does not kill anything in the beginning but the above quote I thought after the second racking and addition of SO2 that the molecular SO2 was high enough to kill bacteria.

 

[JohnT]

My guess is that its the concentrations that are at work here. I guess it all depends on the ppm you have at the time.

 

[MalvinaScordaad]

Look at the PH and the So2 needed to protect a wine and there is your answer. At 25 ppm added to a crush is far below the necessary amount to protect a wine at 3.6 ph. As I said it will stun and slow down growth which is what you want. As fermentation is underway the CO2 formed really takes care of the biological growth of unwanted organisms not the So2.

Yes K meta can kill but it must be in a very strong solution. And it really is not truly a contact killer so those who spray from little bottles may not be that effective. Using bleach is risky from the standpoint of having to make very sure that you have properly rinsed all bleach from the item before use. Whereas a little K meta won't have a negative effect. In my mind Bleach has no use and adds to problems in fermentation operations of a winery.

Also JohnT said I need to do a little re-thinking on some aspects of my process. I have never had a stuck fermentation, trouble getting fermentation to begin, and all of my wines have fermented to dry. This is not to say that I was not always at risk.

We are always looking at our process seeing if there is something better we can do. I do not make wine the same way I did 4 years ago and not the same before that either. As Artisans we have the luxury of employing the best practices without concern of a business considerations. This makes our wine better in the end. As for your 'dry' wine. I will tell you residual sugar and VA levels in amounts not perceptible to taste still can have an effect on long term aging and overall quality. Sending a wine you have made to a lab for testing before you adopted a better practice and comparing that to one which you did may make you a true believer.
Malvina

 

[JohnT]

Thanks Malvina. I think that I will do that.

You seem to really know you stuff. What is your background, location, and how long have you been making wine?