Recurring Sulfur Aroma Issue

I think 5 grams is "standard" for pitch rates for a gallon batch. It certainly wont hurt anything and in my opinion there are many positives for using that much. I have never tried Rhone 4600. The handful of times I have used 71-b I get the same results as you do. I'm starting to lose faith in that yeast. I too control pH, temps, oxygenation, degassing, sanitation and SNA's. Using Fermaid -O, or Dap and Fermaid-K turns out with the same results.

You need to rack enough to not let it sit on the lee's very much. Even knowing that I still get sulferish stink. I have asked around and tons of peps like it.

One of the mead makers at Meridian Hive Meadery in Austin, Texas suggests this for the sulfur/rotten egg smell in a mead:

For a 5 gallon batch, boil 1 Tbsp of bread yeast in 1 cup water in the microwave. Add to fermenter along with 1/2 tsp Fermaid K. Mix and degas until smell returns to a clean honey aroma, about 5 minutes. Naturally, modify the amounts to suit your batch size.

Two things.

I always use a stone and oxygen to oxygenate my wort and must. However I always stir it first to make sure it is completely degases before I turn on the oxygen, otherwise it can do a pretty good imitation of Mt. Vesuvius.

As to "Over Pitching", theoretically you can, but as home brewers we are generally always under pitching yeast, so our "over pitching" iis usually just under pitching, but not by as much.

A Theoretical ideal pitch would be some where in the neighbor hood of:

1 million cells * Milliliters of wort * degrees Plato

Now the reasons for pitching this much yeast is that it is near the maximum amount before you start to get any negative problems from pitching to much yeast (and you you can pitch to much yeast) but because breweries (and I assume meaderies) tend to re-use their yeast they want to make sure they have enough to out compete any other organisms that might have have found their way into their yeast. I know that my friend that owns a craft brewery says that he only buys new yeast of his standard strain once about every 6 months.

Remember though that many of the flavors that people are looking for from your yeast come from the growth of the yeast. So less growing, less esters for flavor. Depending upon what you are looking for this could be a good or a bad thing.


So for you batch that would come to about 435 billion cells or so that you could safely pitch.

Most dry yeast is only about 20 billion cells per gram (if you pitched it dry without re-hydrating it first you kill about 50% of the cell). So even with proper re-hydration (without making a starter) you were only about 20% of the way before you might expect to see any potential problems from over pitching your yeast.

Just for Comparisons, I usually make a 2 Liter starter and that should give me around 250 billion cells for my 5 gallon batches.


Cheers
jay

I typically aerate with oxygen through a diffusion stone once a day for the first 4 days of fermentation, degassing first. I also leave the lid ajar so that air can get in easily during that time. I'll seal things up after a week. I can't say that this will solve your problem since I haven't faced the same problem, but I can say it's worth trying. The worst that will happen is that it won't help, but it also won't hurt.

Have you tried a copper scrubber? I use one in a five gallon ferment and after two days the sulfur was gone.