So I brewed a hefeweizen with a considerable amount of fermentable sugars. Og: 1080, wyeast 3068. The fermentation was explosive. My airlock was coated in foam. I ferment in buckets and the foam took the lid right off. I'm concerned bc i didn't realize the fermentor was open right away. It's quite possible the beer had exposure to the surrounding air for an entire day. Should I be concerned?
More than likely, it's fine. No sense worrying about it, because if it was contaminated, there's nothing you can do about it at this point anyway.
OG of 1.080, is this an Imperial Hefe? An additional concern is your wort/beer most likely had a serious spike in temperature during this period. A jump of 6+ degrees over ambient is likely from your description. This can lead the production of fusel alcohols and if you drop the temp too quickly it could stall the yeast . . . aka; a rock and a hard place. About loosing the lid . . . if you want to feel "less bad" search Google Images for "homebrew blow off".
Here's your brewing tip for the day: If the bottom tip of the plastic shaft on your airlock has cross hairs use some wire snippers to cut them off. This area was likely clogged with krausen and is the culprit for the 'explosion'. Better yet, any time your OG is over 1.070 you should use a blow-off tube.
When you say fermentable sugars, do you just mean a fairly high OG than the norm for a Hefe, or did you add a lot of sugar into the boil? Not that it's a big difference at this point, but curious. At this point, there's not much to be done, but keep in mind there was so much foam and CO2 being pushed out it would be tough for something to get in. IN the future, think about a blowoff tube for high-grav beers - my rule of thumb is anything over 1.060 gets a blow off for the first couple days of fermentation.
Some people, including myself, do not put an airlock on their fermenters until fermentation has slowed down, so you should be just fine.
For new brewers, I think it's worth clarifying that the airlock serves two (or I guess three) functions. It permits carbon dioxide to escape while preventing oxygen from getting in, and it blocks dust, fruit flies, etc. from getting into the beer. As @EvenMoreJesus pointed out, the oxygen-blocking function isn't important early in the fermentation process, and carbon dioxide can escape through any aperture. So you can dispense with an airlock early in the process, but you should take steps to protect the beer from fruit flies, dust, etc. You can cover the hole where the airlock would go with foil or a cotton ball or some other loose-fitting covering—it doesn't take much of a gap to let the carbon dioxide out. But you do generally want something there to keep the bugs out. Obviously this advice doesn't apply in situations where you want microbes from the environment to multiply in your beer, e.g. a lambic. All of that said, for @Abk542's purposes, the beer is probably not infected and quite likely no real harm has been done.
Wy3068 is a beast. I just brewed a dampfbier with this. The OG was only 1.050, and I didn't use a starter. I should have had a blow-off tube on it. It filled the airlock in less than 24 hours.
I learned this the hard way. I had a dubbel with a blow-off tube in the closet, and it sprayed krausen all over the wall. It narrowly missed the coats.
