“Does beer really kill slugs and snails and how? Also, what’s the best way to use it if it does?” Question from Greg of Olympia, Washington
Answer: Yes! Beer is a safe way to attract and kill slugs. The yeasty sweet smell lures them and the ethanol in the beer kills them, or they simply fall into the traps and drown. The key to a smart slug beer trap is covering it in a way that just targets the slugs that feast on your vegetables, hostas, and other favorite plants. (Other insects desirable critters may also be attracted to beer as well as the neighborhood dogs.)
How to Make a Slug-Only Beer Trap
Take an empty lidded plastic container headed for the recycling bin. (A large yogurt or cottage cheese container works well). Cut four elongated holes 3 inches up from the base of the container, so you have enough space to add the beer. Set the container down into the soil, so the holes are just at ground level. Fill the container with cheap beer (the sweeter the better) and the slugs will enter into a blissful demise. Large holes may be needed to accommodate snails.
I hope that this helps!
Black Gold Horticulturist