Mold always makes me nervous, even if there's only a small amount. The reason is because many molds commonly found in kitchens and on food products produce heat-stable toxins. Boiling will kill the mold but any toxins will remain. And given the body form of fungi (excluding the unicellular yeasts), what you see is usually just a tiny fraction of what's actually there.
If it were me, I wouldn't feel comfortable using that extract, even if the risk was relatively low. If you do use it, have your least-favorite relative try the beer first.