I agree with Tom.
If you think you need 10,000 square feet, Go with 20,000. It's a lot cheaper to start off a little bigger than you need, and grow into the space than it is to realize that you've outgrown your space and then have to look for another facility or build new buildings.
We have close to 10,000 and I wish we had 30,000
A few things people never take into consideration are,
Empty barrel storage
Grain storage
Empty glass storage
Finished product storage
Packaging storage
Bottling facility
Just my two cents.