How many recipes are there?

The developer answered my question here, adding:

Trivia: There are actually more than 70 recipes in the game, but various ones like Tutorial Lite don't count toward the Recipe Archivist achievement family.

The official Fiz website, www.brewfiz.com, also advertises "70+ Recipes to discover."

However, not all recipes are unlocked from mice. You can unlock a few through story events; you unlock the Record Breaker from a random, non-story event, and you unlock some from reading recipe descriptions for a hint at a new recipe. For example, the recipe description for Dust Devil says "Vienna Malt might upgrade this little twister..." If you add some Vienna malt, you can unlock a new recipe.

Ten batches of Mousetrap Maibock later, I am confident in stating there are 61 recipes, 60 of which may be normally brewed.