Dosing fresh fruit with k. Meta? How much?

[Ty520]

We have had a couple fermentations that have gone sideways due to contamination that I suspect came from bacteria that was on the fruit we added in secondary. I know a lot of people who do country wines will add k meta to the fresh fruit before they ever add water. Is there any sort of scientific rule on how much to add?

 

[Hazelemere]

1/8 tsp potassium metabisulphite per 2 Imperial gallons of must or water gives you 25 ppm free sulphite as long as the sulphite isn't lumpy.

 

[Ty520]

1/8 tsp potassium metabisulphite per 2 Imperial gallons of must or water gives you 25 ppm free sulphite as long as the sulphite isn't lumpy.

Right, but what about sprinkling over solid fruits? I am thinking perhaps to add the solid fruit to the must at the same as the k meta

 

[winemaker81]

@Hazelemere's dosage is low, according to numerous sources. There is a lot of widely varying numbers, but the ones that I judge the most accurate state 1/4 tsp K-meta in 5 US gallons produces 50 ppm. The pH of the must varies this.

AFAIK, there's no "scientific rule" for how much K-meta to add. It's personal judgment. My best advice is to add 1/4 tsp per 5 gallons of must.

In the USA, wine can contain up to 350 ppm. This is far above any amount I've added, and I use K-meta liberally. The European Union limit is 210 ppm, which is still well above my usage.

 

[Ohio Bob]

Right, but what about sprinkling over solid fruits? I am thinking perhaps to add the solid fruit to the must at the same as the k meta

Can you explain more about your process? Your adding solid fruit in secondary, not in primary?

 

[Rice_Guy]

Wine is a multiple variable food preservation system. ,,, Adding solids that float creates a raft which can be dry enough to support moderate water activity organisms. To be successful the fruit should be submerged or mixed like red grapes get.
Adding chunks of fruit will dilute the typical 11 to 12% alcohol. There will be low ABV and a risk du to that. If fighting infection I would be tempted to do a grain alcohol extract. ,,, or at least wash the fruit in grain alcohol for a few hours.
You are suggesting that meta be used to sanitize raw fruit. SO2 Will combine rapidly with organic material. On a weight basis we typically taste 100 ppm. 50 ppm is the maximum I would try.

 

[Ty520]

Can you explain more about your process? Your adding solid fruit in secondary, not in primary?

Currently we are adding in secondary. The plane was to try to eliminate any bacteria before it touches the wine

 

[Ty520]

Wine is a multiple variable food preservation system. ,,, Adding solids that float creates a raft which can be dry enough to support moderate water activity organisms. To be successful the fruit should be submerged or mixed like red grapes get.
Adding chunks of fruit will dilute the typical 11 to 12% alcohol. There will be low ABV and a risk du to that. If fighting infection I would be tempted to do a grain alcohol extract. ,,, or at least wash the fruit in grain alcohol for a few hours.
You are suggesting that meta be used to sanitize raw fruit. SO2 Will combine rapidly with organic material. On a weight basis we typically taste 100 ppm. 50 ppm is the maximum I would try.

Right.

The goal is to kill off any wild bacteria present on the fruit. We've added it using several methods: whole in mesh bags, pressed for juice... But regardless of method, we want to try to increase confidence in elimination of potential contamination from something on the fruit.

So far, my working proposition is to pitch k meta at the same time fruit goes in

 

[Rice_Guy]

Wine is a multiple variable food preservation system.

Eliminating bacteria typically is done by heating example a material with a pH under 4.0 for 10 minutes at 100C. High pH foods are heated at 15psig steam for about 45 minutes.

Meta will never produce a 100% kill.

 

[winemaker81]

Currently we are adding in secondary.

Why?

I'm not being argumentative. What value do you expect to get by adding fruit post-fermentation, which is likely to renew the fermentation?

 

[Ty520]

Why?

I'm not being argumentative. What value do you expect to get by adding fruit post-fermentation, which is likely to renew the fermentation?

The majority of customers prefer it. (Not my choice... Up to Boss Lady)

 

[Hazelemere]

@Hazelemere's dosage is low, according to numerous sources. There is a lot of widely varying numbers, but the ones that I judge the most accurate state 1/4 tsp K-meta in 5 US gallons produces 50 ppm. The pH of the must varies this.

AFAIK, there's no "scientific rule" for how much K-meta to add. It's personal judgment. My best advice is to add 1/4 tsp per 5 gallons of must.

In the USA, wine can contain up to 350 ppm. This is far above any amount I've added, and I use K-meta liberally. The European Union limit is 210 ppm, which is still well above my usage.

Just for the record in 30 years I haven't had a single contamination or oxidation problem due to dosing must at 25 ppm free sulphite especially whites. I routinely eliminate sulphite on reds but always ferment from a very active starter. 50 ppm is ok but I never use it and have never had a problem. Post ferment espcially on reds after MLF I always use 50 ppm free sulphite. On whites post bentonite and post ferment I always try to get free sulphite in the 25-30 ppm range. I always measure free sulphite in white wines and bottle whites at 25-30 ppm free and reds at about 75 ppm total sulphite. Different strokes for different folks. PS adding bentonite post ferment is dangerous vs mid mid ferment which is perfect since bentonite strips all sulphite.

 

[Rice_Guy]

The majority of customers prefer it. (Not my choice... Up to Boss Lady)

Oh, commercial quantity.

There are products which are fruit concentrates that commercial folks can buy. Example VirginiaDare has excellent clean / low micro “WONF” flavors available in gallon and larger size. or Check out IFF. Home size of several fruit types is available from Coloma Foods. Industry likes WONF since they give the target flavor without the cost of fresh ingredient. If I wanted a high fructose corn syrup punch or a tank of grape wine or a seltzer to taste like something else I would add a gallon of natural flavor.

 

[winemanden]

The majority of customers prefer it. (Not my choice... Up to Boss La

Why?

I'm not being argumentative. What value do you expect to get by adding fruit post-fermentation, which is likely to renew the fermentation?

A bit like an F-pack . Added flavour I suppose.

 

[CaptainPolish]

@Hazelemere's dosage is low, according to numerous sources. There is a lot of widely varying numbers, but the ones that I judge the most accurate state 1/4 tsp K-meta in 5 US gallons produces 50 ppm. The pH of the must varies this.

AFAIK, there's no "scientific rule" for how much K-meta to add. It's personal judgment. My best advice is to add 1/4 tsp per 5 gallons of must.

In the USA, wine can contain up to 350 ppm. This is far above any amount I've added, and I use K-meta liberally. The European Union limit is 210 ppm, which is still well above my usage.

Question for you if you dont mind. Im working with 1 gal jugs, Turning your suggested ¼tsp per 5 gal into 1 gal it would be 1/20tsp if my math is correct. I think at this amount, I may have trouble getting close to that exact ratio. Is it possible to make a solution or something for 5gal and just divide it by volume? Are there better ways to dose 1 gal jugs?

 

[Ohio Bob]

Question for you if you dont mind. Im working with 1 gal jugs, Turning your suggested ¼tsp per 5 gal into 1 gal it would be 1/20tsp if my math is correct. I think at this amount, I may have trouble getting close to that exact ratio. Is it possible to make a solution or something for 5gal and just divide it by volume? Are there better ways to dose 1 gal jugs?

That’s exactly how some people do small additions. Make a water solution with a known amount of Kmeta. You need to know exactly how much water you start with too. Then assume a fraction of the mixed solution will contain a fraction of the Kmeta you mixed in.

 

[winemaker81]

Question for you if you dont mind. Im working with 1 gal jugs, Turning your suggested ¼tsp per 5 gal into 1 gal it would be 1/20tsp if my math is correct. I think at this amount, I may have trouble getting close to that exact ratio. Is it possible to make a solution or something for 5gal and just divide it by volume? Are there better ways to dose 1 gal jugs?

I agree with @Ohio Bob. If I have five 4 liter (1 US gallon) jugs, I put 5 Tbsp water in a sanitized glass and stir in 1/4 tsp K-meta. I add 1 Tbsp of the mixture to each jug.

Note: I don't buy gallon jugs -- I buy Carlo Rossi Burgundy and Chablis, which make great cooking wine at $3-$4 USD per 750 ml bottle, and each comes with a free 4 liter jug!

 

[CaptainPolish]

I agree with @Ohio Bob. If I have five 4 liter (1 US gallon) jugs, I put 5 Tbsp water in a sanitized glass and stir in 1/4 tsp K-meta. I add 1 Tbsp of the mixture to each jug.

Note: I don't buy gallon jugs -- I buy Carlo Rossi Burgundy and Chablis, which make great cooking wine at $3-$4 USD per 750 ml bottle, and each comes with a free 4 liter jug!

Sweet, that will make life easier, and ... DUDE! This whole time! And I could have had like 20gal of wine for free! Ok, doing that going forward! Thank you!

 

[Raptor99]

Question for you if you dont mind. Im working with 1 gal jugs, Turning your suggested ¼tsp per 5 gal into 1 gal it would be 1/20tsp if my math is correct. I think at this amount, I may have trouble getting close to that exact ratio. Is it possible to make a solution or something for 5gal and just divide it by volume? Are there better ways to dose 1 gal jugs?

I bought a small gram scale that is capable of reading to 0.01 g on Amazon for about $10, so I use that to measure Kmeta powder and nutrients. That is much more accurate than using fractions of teaspoons to measure small amounts.

 

[BigDaveK]

Are there better ways to dose 1 gal jugs?

I make a 10% solution and for me it makes everything so much easier. 500 ml distilled water, 50 gr k-meta. You can scale up or down to suit your needs. I usually make 200 ml at a time. Warning - don't smell it. If you're curious, hold it a foot away from your nose. It'll knock your socks off. Freshly made solution doesn't smell much but after a couple hours - yikes!
Then you just need a cheap graduated syringe. There are tables listing how much to use. Basic dose I think is 3.3 ml per gallon but the amount actually needed depends on pH.