I don't own this effect personally but i know someone who did purchase it and it is real beer, taste and all. I know that penguinmagic sells it but i don't know who else does. I'm sure a quick google search will give you a few other stores.
I came up with my own method to turn water into beer. Now, I'm not saying that my method is different or the same as the other methods, but I'm sure it's close. I later found the effect on a website. I just google'd the name and it was a few links down.