Using Potassium Metabisulphate

[Arbe0]

See if this looks right: I am looking into using Potasium Metabisulphate instead of campden tablets. I figured it would be about .03 grams of potasium metabisulphate per each gallon or 1.5 grams per 5 gallons. does this sound right? And yes I can measure that little much. The reason is it would cost less and a bag of it will last a long time.

 

[MaxStout]

I think you have a decimal point off in that second number. A potassium metabisulfite campden has ~0.55g of meta. One tablet treats 20 gallons, so your figure of 0.03g/gallon looks about right. For 5 gallons, you'd need ~0.15g.

 

[Arbe0]

This is what I found: Wikipedia says Campden tablets typically contain 0.44 g each of sodium metabisulfite (plus filler). Each tablet is good for 20 gallons, so if a tablet contains .44 grams for 20 gallons that would be .22 grams for 10 gallons or .11 grams per 5 gallons which means that it would be .022 grams per gallon (I upped it to .03) It is also noted that some formulas use potasium metabisulphate. Campden tablet - Wikipedia

 

[Arbe0]

Thanks Max I just guess I needed someone to verify this.

 

[CascadesBrewer]

The reason is it would cost less and a bag of it will last a long time.

First off, I have read that there is a shelf life on Campden tablets and Metabisulphate. That it will get less effective over time. Is this 1 year or 10 years?

Second, I tossed maybe half a bag of Campden tablets a while back. I think they were still good but a new bag is cheap and I suspect the half bag of tablets was probably 10 years old. If you use 1/2 a tablet per 5 gallon batch, you could brew a batch every 2 weeks for over 7 years before you use up the standard 100 count bag of Campden tablets.

The powder does seem like it might be a little more convenient, where the tablets are more sized for "1 tablet per gallon" for wine (I think).

 

[marc1]

First off, I have read that there is a shelf life on Campden tablets and Metabisulphate. That it will get less effective over time. Is this 1 year or 10 years?

Second, I tossed maybe half a bag of Campden tablets a while back. I think they were still good but a new bag is cheap and I suspect the half bag of tablets was probably 10 years old. If you use 1/2 a tablet per 5 gallon batch, you could brew a batch every 2 weeks for over 7 years before you use up the standard 100 count bag of Campden tablets.

The powder does seem like it might be a little more convenient, where the tablets are more sized for "1 tablet per gallon" for wine (I think).

It's good maybe a couple-few years if stored cool, dry, and sealed:

https://blog.homebrewing.org/how-to-tell-if-your-potassium-metabisulfite-is-old/