Confused about potassium metabisulfite

[Cowboy77]

Hello everyone. Just getting into winemaking, and I really appreciate any help/advice that you wine connoisseurs can give me to a few questions I have. First batch of wince almost done with primary fermentation (2 1/4 gallons). Figured I'd do something simple with my first batch, so I decided on Welch's 100% concentrate. Will be racking into 2 one gallon secondaries in the next day or two with airlocks. I've been reading and trying to understand about when to add potassium metabisulfite to wine and if I need to add it, but the more I read, the more I'm confused. So here goes:
1) When making wine from concentrate, should you add potassium metabisulfite to must 12 hrs before adding yeast, or is this true only for wines made from fresh berries or fruit to kill the wild yeast?
2) Since this wine is from concentrate, do I need to add potassium metabisulfite to the secondaries before first racking, or is this true only if wine is made from fresh berries or fruit?
3) If so, how do I measure out that small of an amount, since what I've read says use 1/4 teaspoon for 5 gallons (I have a 2 gallon batch going)
4) I've read to add potassium metabisulfite at every other racking. Do I need to do this since this wine is from concentrate and not from berries/fruit and is this true for every batch of wine you make?
5) Before bottling, do I need to stabilize (using potassium metabisulfite and potassium sorbate) since this wine is from concentrate and not from fruit?
6) Should you stabilize every batch of wine before bottling, whether you back-sweeten or not, or whether it's made from concentrate or fresh berries or fruit, to ensure no further fermentation?
Thanks so much in advance for any help/advice you all can give me! Randy

 

[stickyfinger]

if your starting material is pasteurized, i don't see why you'd add sulfites. Sulfites at later stages protect the wine from staling, but it's best to know the pH of the wine so you add the right amount of sulfites.

 

[jgmillr1]

Hey Randy. Welcome to winemaking. Hopefully this will clarify the use of sulfites for you.

You should use sulfites the same way regardless of whether it is from concentrate or fresh fruit. Bacteria, wild airborne yeast and oxygen don't care how that delicious batch of sugary liquid got there.

For small batches, you can measure our small amounts of sulfites and mix it up in water. Then use whatever portion you need to dose with the sulfites you wanted. So, if you wanted use the right amount for 2 gallons, mix up the 1/4 tsp in 10ml of water and use 2ml in each gallon. You can also use campden tablets and break them into pieces if needed.

You should use *always* sorbate and sulfites when you backsweeten the wine or it will referment. If the wine was fermented dry and not backsweetened, then you can skip the sorbate and just use sulfites.

Hope that helped. Post more questions as you get them. Lots of folks here are glad to help.

 

[bernardsmith]

Hiya Cowboy77 - and welcome.
I guess I take a slightly different tack. Sufites have two benefits - one is to disable any wild yeast in the juice and so help your pitched yeast gain a strong enough toe-hold to create the environment they prefer and one which any wild yeast cells are likely to dis-prefer. However, if you know that the juice you are fermenting has been treated to kill off or otherwise disable any wild yeast then I don't see the value in adding sulfites before you ferment.
After fermenting free sulfur dioxide act to inhibit oxidation. The amount of sulfur dioxide really depends on the pH - the more acidic the wine is the less SO2 you need, the less acidic the more SO2 you need. But for the most part the amount of free SO2 produced by the amount of K-meta in a campden tablet is more or less enough to protect a gallon of wine (so 3 gallons need 3 tabs - although it is far less expensive to simply make a solution of K-meta at the appropriate concentration and not add the tablets) . What many/most wine and mead makers do is rack their wines /meads onto some K-meta or crushed Campden tablet each time they rack or each second time they rack and as they bottle.
Last point , as jgmillr1 states if you are going to stabilize your wine before backsweetening (and you need to somehow stabilize or remove every last yeast cell) then the only effective way to do that is to add K-meta and K-sorbate IN TANDEM - adding only one will not work.

 

[Cowboy77]

Thanks so much for the replies! This really helps me out. I just finished racking from primary to secondaries w/airlocks. I did not add any K-meta before fermenting, but took the advice and added the K-meta in each of the secondaries before racking. Used the method jgmillr1 described above using a 5 ML syringe (10 ML water, 1/4 tsp K-meta, and added 2 ML in each secondary). I do not have a method to measure Ph, so hopefully the amount I added will be sufficient. I'll probably add K-meta every other racking from here on out. If down the line before bottling I need to backsweeten, I will definitely use the K-meta and the K-sorbate as was mentioned above as well. Thanks again for taking the time to give me this advice! Randy