I made apfelwein the other day, and without thinking used a packet of dry yeast that had been sitting in my Arizona (very hot) garage for a month. After 24 hours I didn't notice any activity...and assumed I'd just killed it.
Then I wake up this morning and notice something unusual. The airlock is bubbling like crazy and there is an inch of krausen/bubbles at the top.
Now I know that Montrachet shouldn't do that, as I've made apfelwein quite a few times.
Do I have a foreign yeast in there?