Killing Wild Yeast Failed

[jackl]

I make small batches (5-10 gallons) of pretty decent wine wine from my home grown Marquette grapes. As usual, after the crush I added Potassium Metabisulfite according to the dosage on the container of 1/4 tsp per 5 pounds. My grapes were pretty clean this year. However, we had a very wet and cloudy summer in upstate NY and despite vine pruning and leaf pulling my average brix was only 20 and pH 3.2 so I'll be addressing this. I had to harvest as the yellow jackets were begining to wreak havoc! Anyway, the next day when I checked the must, it was already fermenting. I still need to make some adjustments before pitching the yeast to get the SG closer to 1.095. Should I give it another dosage of Potassium Metabisulfite and let it sit a day to kill the wild yeast before I move forward?

 

[cmason1957]

If 1/4 tsp per 5 pounds didn't kill it off, I don't think it's going to stop with more, unless you get to enough to half all fermentation. I'd pitch your preferred yeasty and hope it takes over. I generally add 1/4 tsp per 50 pounds.

 

[NorCal]

Yea, should be 1/4 tsp per 40 pounds or so. The fact you got something fermenting is pretty impressive.

 

[balatonwine]

according to the dosage on the container of 1/4 tsp per 5 pounds.

Was that a typo? Normally it is 1/4 tsp per 5 gallons not pounds...

Anyway, the next day when I checked the must, it was already fermenting.

Content of the must may bind up the SO2, negating its effect. Anything from particulate matter to chemical compounds in the must may bind SO2.

There are also wild yeasts that have reasonable high SO2 tolerance.

Should I give it another dosage of Potassium Metabisulfite and let it sit a day to kill the wild yeast before I move forward?

Personally, I would recommend testing your free SO2 before adding more. One should not over dose their wine. There are inexpensive test kits available if you do not already have one.

Else, either adding more K-meta, or simply pitching commercial yeast may be only guess work, an experiment, or an artistic endeavor -- you can choose what suits you best.

 

[NorCal]

This is a calculator I made to calculate the amounts of the different elements needed for fermentation, confirming the 40 pounds; a 1/4 tsp of SO2 will weigh 1.5-1.6 grams.

 

[balatonwine]

This is a calculator I made to calculate the amounts of the different elements needed for fermentation, confirming the 40 pounds

And confirming 40 pounds = 5 gallons of must. I find it easier to think and process chemical additions in volumes myself. But some think in weight, and why I was wondering if maybe the OP had a typo, as I would be very curious to learn a commercial package of K-meta was suggesting adding 1/4 tsp to only 5 pounds of grapes/must.

 

[eightysixCJ]

I make small batches (5-10 gallons) of pretty decent wine wine from my home grown Marquette grapes. As usual, after the crush I added Potassium Metabisulfite according to the dosage on the container of 1/4 tsp per 5 pounds. My grapes were pretty clean this year. However, we had a very wet and cloudy summer in upstate NY and despite vine pruning and leaf pulling my average brix was only 20 and pH 3.2 so I'll be addressing this. I had to harvest as the yellow jackets were begining to wreak havoc! Anyway, the next day when I checked the must, it was already fermenting. I still need to make some adjustments before pitching the yeast to get the SG closer to 1.095. Should I give it another dosage of Potassium Metabisulfite and let it sit a day to kill the wild yeast before I move forward?

I added the same as NorCal to my NY grapes (Frontenac, brix 21 pH 3.3). K-meta added after the crush, I noticed fermentation beginning at the end of crush day. I moved up my schedule and pitched yeast. So far, fermentation proceeding well although faster than I expected.

Tom

 

[Gilmango]

This is a calculator I made to calculate the amounts of the different elements needed for fermentation, confirming the 40 pounds; a 1/4 tsp of SO2 will weigh 1.5-1.6 grams.

View attachment 79027

Sorry to threadjack, but this chart is very timely for me, thanks! I picked wine grapes for the first time last Saturday, and happily got just over 4x this amount (163# of Mourvedre from Brentwood, CA), although I have less must than your chart indicates (more like 16-17 g). I screwed up a bit and added my yeasts and Go Ferm before my SO2, have now added my Fermaid K as well. When fermentation stops will the cap no longer float on top?

I don't have any MLF ingredients, so I cannot co-innoculate. From what I have read, if I don't add MLF it will very likely go through MLF anyways, unless I add something like Lysozyme to surpress that. So either way I need to get an order placed, I guess adding MLF is the way to go for my very first non-kit red wine, rather than waiting on nature to do the MLF. Great to know I don't need to use a whole satchel of CH16, presumably I can store the rest for future batches?

My other big challenge with be pressing without a press. I'm thinking my 50 quart Igloo with notched CPVC pipes leading to a ball valve (for mashing and lautering all grain beer) might actually do a good job, or maybe the notches will quickly get jammed with skins and pulp. Similarly the nylon mesh bags I use for quicker 'brew in a bag' mashes could also help. Or I might try drilling hundreds of holes in a bucket and making a two bucket press which I saw on youtube. Hoping I can get enough to fill my 30 liter Speidel to the very top and use as a secondary, but without a press that might be tough.

 

[jackl]

Thanks for all of the input! I did recheck the LD Carlson Potassium Metabisulphite dosage and it says "To kill wild least add 1/4 tsp per 5 gallons of must". I crushed and de-stemmed 78 lbs of grapes which yielded about 8 gallons of must which should give me lose to 5 gallons of juice. Therefore, I dosed it with 0.4 tsp. I do need to purchase a SO2 test kit. Usually I just check the Brix/specific gravity, TA and pH. I track every stage in a spreadsheet with embedded formulas.

In any event, today I made my sugar adjustments to raise my Specific Gravity from 1.080 to 1.095 which is the level I usually strive for, added yeast nutrient, a bit of tannin and made a yeast starter with Red Star Premier Rouge. I pitched it this morning and this evening it's fermenting vigorously.

I usually give it 5-6 days of primary, then I'll press. Since I have to manage the pH due to our location, I'll run MLF after secondary and maybe even do a cold stabilization to drop the tartrate crystals. I may oak age it too. I try to get the pH to around 3.4-3.5 before I bottle.

Now we wait!

 

[CDrew]

Sorry to threadjack, but this chart is very timely for me, thanks! I picked wine grapes for the first time last Saturday, and happily got just over 4x this amount (163# of Mourvedre from Brentwood, CA), although I have less must than your chart indicates (more like 16-17 g). I screwed up a bit and added my yeasts and Go Ferm before my SO2, have now added my Fermaid K as well. When fermentation stops will the cap no longer float on top?

I don't have any MLF ingredients, so I cannot co-innoculate. From what I have read, if I don't add MLF it will very likely go through MLF anyways, unless I add something like Lysozyme to surpress that. So either way I need to get an order placed, I guess adding MLF is the way to go for my very first non-kit red wine, rather than waiting on nature to do the MLF. Great to know I don't need to use a whole satchel of CH16, presumably I can store the rest for future batches?

My other big challenge with be pressing without a press. I'm thinking my 50 quart Igloo with notched CPVC pipes leading to a ball valve (for mashing and lautering all grain beer) might actually do a good job, or maybe the notches will quickly get jammed with skins and pulp. Similarly the nylon mesh bags I use for quicker 'brew in a bag' mashes could also help. Or I might try drilling hundreds of holes in a bucket and making a two bucket press which I saw on youtube. Hoping I can get enough to fill my 30 liter Speidel to the very top and use as a secondary, but without a press that might be tough.

So, @Gilmango I am wishing you the best of luck. But if you got those Brentwood grapes through calwinebroker.com (Michael) they are very problematic for unknown reasons. Maybe you got from a different source, I hope so. I had problems with those in 2019 and another member on this forum is having problems now in 2021.

You need to follow your fermentation with a hydrometer. There is no other way. Sure, eventually the cap won't float but by then you are way behind by several days. Press when your brix hits single digits. I like to press at 1 brix and let it finish in carboys or stainless kegs.

MLF is up to you. I'd do a controlled addition any time, but your call. The sooner the better. Relying on mother nature may work, but it may not too, and you'll be left with unstable wine. You do not want to prevent MLF in a red wine. Instead, you want to make sure it happens. And the last thing you want, is for it to happen in the bottle, because it will and lead to bottle bombs and fizzy wine.

With regards to pressing, I have a wine making friend who only does free run wine. He does not press. He makes very good wine. In your case, you would loose about 20% of your yield but it's not crazy. The bucket press thing looks like it would work, do that if you can't rent a press.

Regarding the Speidel containers-they look good, but they are very hard to completely fill without any airspace. They are actually made for making beer. The vessel wall is thin and fairly permeable to Oxygen. Wine is a much longer process. You will want to exclude oxygen. You might consider carboys which are much easier to fill with only a tiny fraction of airspace and are impermeable to oxygen. I have another winemaking friend that uses Speidel containers and his wine has excessive VA and ethylacetate. After fermentation, air is the enemy. Be ruthless and eliminate it from your wine. Eliminate surface area where ever you can. Once you've gotten good at the process, the you can consider controlled oxygen ingress like barrels or Flextanks.

Like I said, good luck. WIne needs a good start and then lots of time. Pay attention to details. Exclude Oxygen. Eliminate headspace. In 2-3 years, you'll know how you did!

 

[cmason1957]

Thanks for all of the input! I did recheck the LD Carlson Potassium Metabisulphite dosage and it says "To kill wild least add 1/4 tsp per 5 gallons of must". I crushed and de-stemmed 78 lbs of grapes which yielded about 8 gallons of must which should give me lose to 5 gallons of juice. Therefore, I dosed it with 0.4 tsp. I do need to purchase a SO2 test kit. Usually I just check the Brix/specific gravity, TA and pH. I track every stage in a spreadsheet with embedded formulas.

I'd be interested to see the directions where you read that. It just seems to be a whole bunch more than I remember ever reading and it seems some of the guys who have been around a fairly long time might agree. Can you post a link to it or a picture of where you read it?

 

[Gilmango]

So, @Gilmango I am wishing you the best of luck. But if you got those Brentwood grapes through calwinebroker.com (Michael) they are very problematic for unknown reasons. Maybe you got from a different source, I hope so. I had problems with those in 2019 and another member on this forum is having problems now in 2021.

You need to follow your fermentation with a hydrometer. There is no other way. Sure, eventually the cap won't float but by then you are way behind by several days. Press when your brix hits single digits. I like to press at 1 brix and let it finish in carboys or stainless kegs.

MLF is up to you. I'd do a controlled addition any time, but your call. The sooner the better. Relying on mother nature may work, but it may not too, and you'll be left with unstable wine. You do not want to prevent MLF in a red wine. Instead, you want to make sure it happens. And the last thing you want, is for it to happen in the bottle, because it will and lead to bottle bombs and fizzy wine.

With regards to pressing, I have a wine making friend who only does free run wine. He does not press. He makes very good wine. In your case, you would loose about 20% of your yield but it's not crazy. The bucket press thing looks like it would work, do that if you can't rent a press.

Regarding the Speidel containers-they look good, but they are very hard to completely fill without any airspace. They are actually made for making beer. The vessel wall is thin and fairly permeable to Oxygen. Wine is a much longer process. You will want to exclude oxygen. You might consider carboys which are much easier to fill with only a tiny fraction of airspace and are impermeable to oxygen. I have another winemaking friend that uses Speidel containers and his wine has excessive VA and ethylacetate. After fermentation, air is the enemy. Be ruthless and eliminate it from your wine. Eliminate surface area where ever you can. Once you've gotten good at the process, the you can consider controlled oxygen ingress like barrels or Flextanks.

Like I said, good luck. WIne needs a good start and then lots of time. Pay attention to details. Exclude Oxygen. Eliminate headspace. In 2-3 years, you'll know how you did!

Thanks so much for the detailed reply! Sadly, Michael of calwinebroker was my source for the Mourvedre grapes, picked at the old Tamayo (sic?) farm/vineyard on Byron highway in Brentwood. Love to know more about the problems encountered with those grapes by you in 2019, and by another member this vintage. Flavors off? Chemistry off? Sluggish ferments? Either way sounds like I may not have picked the right grape and vineyard for my first foray into wine from grapes. But I'd love to learn what adjustments might be made to make the best wine I can from what I have. OK, just poked around and on WMT and it sounds like the color was way off, and not a great smell either. Damn. Being completely new to wine from grapes I did not notice anything off visually.

I will press or free run this weekend. The cap is no longer rising way above the surface, but I am still having real problems getting reliable hydrometer readings as with all the pomace it does not seem to be floating freely. When I try to put in the wine thief that also gets clogged with pomace. Seems like I'd need to dip in a sanitized measuring cup, strain that to another before I could finally get a reading. Is there a better way for someone without a refractometer? Either way get the juice off the pomace as best I can tomorrow (just 7 days after the pick), and maybe skip doing a second run wine if the grapes are suspect already.

I will start MLF as soon as my order arrives from morewine, got CH16 and Acti-ML.

Thanks for the warning on the Speidel. I bought it so I could do EM on the kit wines I started making during the pandemic - so never used for more than 3-8 weeks and sealed under airlock around 1 brix. But I was hoping that if I could fill it to the top that their small oxygen transfer might mimic the effect of the barrel, plus it seems like a good size and I only have one carboy free at the moment, but if I bottle a beer this weekend I can have two carboys free, and use the Speidel for my next beer. So I guess that is the plan now. Thanks again.

 

[David Violante]

I added the same as NorCal to my NY grapes (Frontenac, brix 21 pH 3.3). K-meta added after the crush, I noticed fermentation beginning at the end of crush day. I moved up my schedule and pitched yeast. So far, fermentation proceeding well although faster than I expected.

Tom

I had the same exact experience as you did Tom… I also have Frontenac from the same supplier as you. I crushed 40 lbs. / 5 gallons and 1/4 tsp. Kmeta. Active ferment overnight!

 

[pete1325]

Is it necessary to kill off the native yeast before introducing a store bought yeast?

 

[Gilmango]

Is it necessary to kill off the native yeast before introducing a store bought yeast?

It is very common but not necessary. Basically, if you have decided to use a commercial yeast strain, that strain being added in numbers will generally become the dominant strain even if it is competing with native yeast strains and bacteria. But most who add commercial yeast want to clean the slate of competing wild yeast and bacteria by typically adding 50 ppm of SO2 to the volume of the must after crushing (more or less depending on pH, more if grapes are in really poor shape).

But at the other end of the spectrum some wine makers ferment with just the native yeast and bacteria. So it stands to reason that you can add a cultured commercial yeast without first having killed off everything.

 

[winemaker81]

But most who add commercial yeast want to clean the slate of competing wild yeast and bacteria by typically adding 50 ppm of SO2 to the volume of the must after crushing

If planning malolactic fermentation, skip the SO2 as it inhibits the MLF bacteria.

 

[Gilmango]

If planning malolactic fermentation, skip the SO2 as it inhibits the MLF bacteria.

Good point, this both confirms what you are saying, but also notes that the typical 50 ppm which many add at crush will generally not prevent MLF (2nd paragraph).

Most winemakers know that a high “free” SO2 level can inhibit ML bacteria, and that if you want to carry out an MLF then you usually don’t sulfite the wine until after the fermentation has completed. However, it is crucial to realize that “bound” SO2 also has a negative affect on the bacteria. This is because while “bound” SO2 is 5 to 10 times less active than “free” SO2 , at high enough levels it too can hinder bacterial growth. So, if you want to do an MLF on a particular wine not only do you need to be aware of how much “free” SO2 is in the wine, you also need to keep tabs on the portion that is “bound” as well. These two portions combined are referred to as “total” SO2 and the following SO2 levels are recommended by Lallemand as being favourable MLF conditions: 0–10ppm “free”, and 0–30ppm “total”.

Note that in general, if you crush and add a single 50ppm “total” SO2 addition up front, by the time the fermentation is over you will usually have around 20–25ppm as “total” and 0–10ppm as “free”. In other words, you should be well within the recommended ranges. (Keep in mind, however, that this amount will vary with different must compositions and fermentation temperatures).

5 Steps to a Succesful Malolactic Fermentation (MLF) | MoreWine beyond SO2 the article also discusses the impacts of temperature, pH, abv, and nutrition on successful MLF.