When drafting a patent application, your patent attorney will try to construct the claims to allow for as broad of protection as possible, however, during the prosecution phase of the application, you may be required by the examiner to abandon claims or narrow their scope.
Applying for a patent is done through the United States Patent Office. I highly recommend that you enlist the services of a registered patent attorney. Get references and make sure you meet with the attorney before snagging them.
The prototype question was addressed in post #29, sourcing question is in post #22
Finding a good patent attorney should be through word of mouth, but you can also get a complete list of registered patent attorneys at http://www.uspto.gov/
If your idea is really that great, you might want to partner with someone who is willing to assist you with the funds necessary to obtain the patent. Giving up a portion of the equity is better than not doing anything at all.
If you have an interesting beverage idea, don't let anyone know how you made it. You really have 2 choices in commercializing...(1) become an entrepreneur and produce it yourself. This worked well for VitaminWater. He sold his company to Coca-Cola this year for billions, or (2) license the concept to an existing beverage company. While obtaining a patent will be difficult, filing a trademark on a clever and catchy brand might be much easier.
I must disclose here that there will be a search on Edison Nation later this month for a new beverage. More details will be available online at http://www.edisonnation.com/