I just finished a batch of Belgian strong dark, cooled to 80 and pitched a starter of WLP530 about 30 minutes ago. I have the bucket in a swamp cooler of 65 degree water, so I just went to check on it to see if it was starting to suck back sanitizer yet, since that's fairly common when the wort is still cooling. To my surprise, the thing was already bubbling. Is it even possible that the yeast are already going at this thing hard enough to produce that much co2? This is really my first time making a starter, but it just doesn't seem normal. Sorry for the noob moment, I'm now stepping away from the beer to let it do it's thing.