Campden vs Potassium Sorbate

[Blackbox_Brewing]

I've read of people using campden tablets (potassium metabisulfate) to sanitize cider from wild yeasts and using potassium sorbate to stop fermentations when a desired FG is reached. So my question is, what's the difference? Yes, I obviously get that they're 2 difference chemicals, but what's the difference in effect?

Couldn't I stop a fermentation with campden tablets the same way you can use potassium sorbate? Couldn't I use potassium sorbate to stop wild yeasts? Their intended use seems to be close to identical...

 

[BenjiEDF]

Well I'm new to this stuff too. From what I've read campden is useful with racking (exposing wine, cider etc to oxygen) after the fermentation is complete to prevent oxygenation. It can also be used prior to pitching the yeast (use and wait 24 hrs) to suppress wild yeast. People have hinted at it's ability to halt fermentation but that is usually struck down by experienced people rather quickly. Campden is probably used more often in wines than cider because of the longer aging process.

Potassium Sorbate is a preservative and will stop fermentation, once added game over. After adding this if you want to carbonate it will have to me forced.

If I'm wrong then correct me guys.

 

[Thunder_Chicken]

I believe the difference has to do with the relative strength of wild yeasts vs. pitched yeasts. Properly dosed campden can take care of low concentrations of weak wild yeasts, but the amount of campden required to shut down a ferment would be enough to taste, and so potassium sorbate is better for that application. Sulfites in campden also scavenge oxygen so they are also used in racking to keep oxidation to a minimum, and campden is also used to precipitate chlorine and chloramines in water for brewing.

Campden and sorbate are often used together when stabilizing sweet wines for ageing.

 

[Randzor]

Capdmen tablets dissapate over time vs the preservative. In addition if you use to much capdmen over time you will lose taste of it and may be tempted to over treat your future brews.

 

[Jacob_Marley]

The sulfite makes yeast retarded.
The sorbate makes yeast impotent.
Use both of them and it makes the yeast in your cider retarded and impotent ... but it does not kill the ones currently living.
Currently living yeasties must die of old age, famine, and too much alcohol etc. (just like us I suppose)

Sorbate does not stop fermentation. Sorbate PLUS time stops fermentation. Time so that the elder yeasties die off without any young'uns ... end of the bloodline.

Reading up specifically on sorbate ... and on sulfites, will tell you all you need to know about what they do.