Moldy corks?

mjhughes said:

p.s. I can provide pictures if needed.

Click to expand...

Please do - that may be helpful.

These are too fuzzy to say anything definitive about what's going on. The color suggests mold, but I can't tell for sure. I'd say, under the circumstances, pull one of the nastier looking corks and check it definitively for mold. If you catch it early enough you can open all the other bottles, treat your mead with sulfites to kill off any mold spores that are in there (you don't even need to pour out the mead and re-bottle, but you can if you want to), rinse any new corks that you will use with a fairly concentrated solution of metabisulfite with a little acid blend added (the acid blend lowers the pH of the rinse water, which will help to activate the sulfite), and then re-cork.

I can't see the cork well enough to say much from the pictures. Have you pulled one out to examine it closely?

Most mold colonies will form tendrils after a time, but if you do pull a cork to examine the black stuff more closely, sniff at it and touch it with your finger. Mold, as well as other spoilage organisms, will generally smell bad (spoiled or "musty") and feel slightly slippery to the touch.

To add a measured dose of sulfite to each bottle, it is better to mix up a bulk solution that when a measurable amount is added to the mead in each of the bottles, will dose each with an amount equivalent to 100 to 150 ppm free SO2. Measuring out the correct amount of tablets or powder to add to each bottle individually would be too difficult.

So, let's run through a little calculation to see how much you'll need. You have 12 bottles that need to be dosed, and each one contains about 750 ml of mead. You can probably add another 5 ml of liquid to each bottle and still get a cork in with no problem, so let's assume the total volume in each bottle will be 755 ml after you make the addition. NOTE: 5 ml is not a lot - it is almost exactly 1 level teaspoon.

Anyway, back to the calculation. Let's assume that your mead is a nominal pH of 3.5, so you want (for the sake of argument) to get 100 ppm of free SO2 in each bottle, but you should assume that some amount of what you add will be "bound" by other compounds in the mead. So, let's shoot for a total addition of 150 ppm to each bottle. Conveniently, one part per million is the same as 1 milligram per liter, so 150 ppm is 150 mg per liter. Since you will have 0.755 liters of liquid in each bottle, you'll want to add 0.755*150, or 113.25 mg of SO2 to each bottle. Assuming you are using potassium metabisulfite which is 57% SO2, you'll want to add 113.25/0.57 = 198.68 mg of K-meta powder, or the equivalent in campden tablets, per bottle.

Call that 200 mg just to do everything in round numbers. Making up a solution good for 12 bottles, take 200mg * 12 = 2.4 grams of K-meta powder, and dissolve that completely in 5 * 12 = 60 ml of water. Then take one tsp of that K-meta solution and add it to each bottle shortly before you cork them with new corks.

The math looks right.

You definitely need some new corks - in this case I might suggest synthetic or Zorks.

2.4 grams of metabisulfite = 5 & 1/2 tablets. Cutting them isn't the easiest thing to do, but you can do it by hand close enough if you use a boxcutter or single edge razor blade. Close to half is good enough. If you don't want to mess with cutting, using six will give you slightly more sulfite per bottle but that won't hurt anything.

60 ml of water is 12 teaspoons, or 4 tablespoons, or a quarter of a cup.