I just tried a new technique on a ferment and had a sulphur smell coming off the jars after a few days. I usually cover wild ferments with cheesecloth for a few days to start the fermentation but i was going to experiment with putting the lid on as soon as the mash is poured into the jars. Loose lid of course so gas can escape but oxygen can't get in. I read up on the sulphur and read that it is normal for some types of yeast to let off a sulphur like smell and that it is safe. I'm going cook my sauce and see if that sulphur goes away or is in the final product which would go straight to the trash. Experiment went well in the terms of the fermenting because it bubbled within 24 hours and kept going strong till the end.