potassium metabisulphite confusion.

[MJJ]

My bottle of potassium metabisulphite was almost empty so I picked up a bag at the local home brew store. The instructions for dosage is different. Is this normal? This is the dosage for both.

Original bottle.
Usage: 1/8 tsp per gallon = 100 ppm of free so2

New bag.
Usage: 1/4 tsp per 5 gallons (yields 40-45 ppm so2)

Does anybody understand this cause I don't?

Also, I use 3 gallon carboys, Would the "1/4 tsp per 5 gallons" be too much for a 3 Gal carboy? (Pre fermentation & Post fermentation)


Thank You

 

[Legitapotimous]

Ok correct me if i am wrong, but was you first bottle liquid? Same manufacture? As u will notice with LD Carlson, nutrient and Lalvin products, a dosage difference for similar products is common. So unless its the same brand or manufacturer, Id say its just a different blend and refer to the label.

 

[MJJ]

Ok correct me if i am wrong, but was you first bottle liquid? Same manufacture? As u will notice with LD Carlson, nutrient and Lalvin products, a dosage difference for similar products is common. So unless its the same brand or manufacturer, Id say its just a different blend and refer to the label.

The first bottle was a 4 oz powder by Crosby & Baker

 

[wayneb]

The source of confusion comes from the fact that there are two chemicals generally referred to as "metabisulphite" (sodium and potassium) and each yields slightly different amounts of free SO2 when dissolved in liquid. Further adding to the mess is that some sets of instructions assume that all the SO2 added is "free," while others err on the safe side and assume a certain percentage is "bound," reacting with other chemicals in the mead or wine and then not able to exert any antimicrobial effect.

I think I like the rule of thumb that I got off of a More Winemaking instructional article a couple of years ago:

"If you don’t have a scale:
¼ tsp SO2 per 5 gallons (US) = 50 ppm. Fudge accordingly.
1 tsp SO2 = 5.9 grams."

This rule of thumb makes several conservative assumptions about how much SO2 is active, so if you follow it, you'll always be on the safe side, and adding a little extra sulphite usually doesn't hurt anything.

 

[MJJ]

The source of confusion comes from the fact that there are two chemicals generally referred to as "metabisulphite" (sodium and potassium) and each yields slightly different amounts of free SO2 when dissolved in liquid. Further adding to the mess is that some sets of instructions assume that all the SO2 added is "free," while others err on the safe side and assume a certain percentage is "bound," reacting with other chemicals in the mead or wine and then not able to exert any antimicrobial effect.

I think I like the rule of thumb that I got off of a More Winemaking instructional article a couple of years ago:

"If you don’t have a scale:
¼ tsp SO2 per 5 gallons (US) = 50 ppm. Fudge accordingly.
1 tsp SO2 = 5.9 grams."

This rule of thumb makes several conservative assumptions about how much SO2 is active, so if you follow it, you'll always be on the safe side, and adding a little extra sulphite usually doesn't hurt anything.

So ¼ tsp SO2 is safe for a 3 Gal carboy twice?

 

[wayneb]

If you're using it as part of stabilization after fermentation is over, yes. If you are planning on adding that much to knock out wild yeasts prior to pitching your yeast strain, that is a little on the heavy side, but if you wait an extra day (as in 48 hrs min rather than 24) after the addition before you pitch, you'll be OK with that, too.

 

[MJJ]

If you're using it as part of stabilization after fermentation is over, yes. If you are planning on adding that much to knock out wild yeasts prior to pitching your yeast strain, that is a little on the heavy side, but if you wait an extra day (as in 48 hrs min rather than 24) after the addition before you pitch, you'll be OK with that, too.

Thank You.

 

[fivecats]

If you're using it as part of stabilization after fermentation is over, yes. If you are planning on adding that much to knock out wild yeasts prior to pitching your yeast strain, that is a little on the heavy side, but if you wait an extra day (as in 48 hrs min rather than 24) after the addition before you pitch, you'll be OK with that, too.

The time clarification is much appreciated! I'm planning on doing this with my orange zest/OJ before putting everything into a secondary and you just saved me from asking this question!

 

[hepcat]

I've made 9 gallons of melomel mead with whole fresh oranges and not had any contamination problems. What I did is thoroughly wash the oranges with soapy water and a vegetable scrub brush, rinse, then sanitized them before cutting them up and adding them to the must.

 

[Chevette Girl]

I've made 9 gallons of melomel mead with whole fresh oranges and not had any contamination problems. What I did is thoroughly wash the oranges with soapy water and a vegetable scrub brush, rinse, then sanitized them before cutting them up and adding them to the must.

That's what I do (although usually don't even bother sanitizing), some folks will always use sulphites 24 hours before pitch, I only do for fruits that I know will go funky before the pectinase has done its thing (for me that's only pears).

 

[tweak'e]

Original bottle.
Usage: 1/8 tsp per gallon = 100 ppm of free so2

New bag.
Usage: 1/4 tsp per 5 gallons (yields 40-45 ppm so2)

hate to point out the bleeding obvious here but.......

original is 5/8 tsp per 5 gallon 100ppm
new is 5/8 tsp per 5 gallon 100ppm

wheres the problem?

 

[wayneb]

There isn't one, unless you're unfamiliar with dealing with ratios and measurements in other than decimal divisions. But a newbee meadmaker should not have to already be facile with fractions, in order to make a good mead! ;D

(That's my opinion - others will undoubtedly disagree!)