I use a copper immersion chiller. The last time I used this strain, was for a hefe. No sulphur. The time before was a dunkelweizen that produced sulphur. I guess I kegged it before all the sulphur had dissipated. Now, another dunkelweizen, and sulphur again. I'll give it plenty of time before kegging, 2 weeks, maybe even 3. I've never used any weizen yeast strain besides Weihenstephan.
As the fermentation subsides, will the sulphur still be able to get past the airlock? Do I want to remove the airlock, and put a piece of foil over the top of the carboy?