I taught my 3 year old son how to count by counting bottles as I bottled beer.
My advice, don't make a big deal about it. Both my boys ask me what I'm doing and I simply tell them "daddy's making beer".
Sometimes my 3 year old will ask more detailed questions about the process and I do my best to explain it too him in a way a 3 year old can understand.
Don't sweat it your kid will fine.