Is the word 'recipe' an abstract noun?

I'm studying English to teach as a foreign language and can't completely grasp the difference between concrete and abstract nouns. For example, "recipe" is a noun. I understand that a recipe card would be a concrete noun but would recipe alone be an abstract noun i.e. an idea?

TIA Eloise

John Lawler wrote:

Recipe can refer to a text (which is pretty abstract, but is precise and can be repeated or analyzed), any number of physical objects that present it (like a file card, which is totally concrete), or some completely imaginary — hence abstract — metaphorical use, like recipe for disaster. No noun is ever always abstract, just like no verb is ever always transitive.

nnnnnn asked:

If no noun is ever always abstract, how does one make dread or wistfulness concrete? Can you please expand on what I'm misunderstanding?

John Lawler clarified:

Easy; use them to name something. It's the opposite of metaphor, which makes abstractions by mismatching concrete phenomena.