In the cola wars, there's one place to look and see who has the fizz and who's flat. Take a quick peek at the cash flows and you will see that PepsiCo (NYSE:PEP), not Coca-Cola (NYSE:KO), is it.

On a trailing price-to-earnings basis, Pepsi trades at about a 10% discount to Coca-Cola. No surprises there. When you think about the power of Coke's brand around the world, that makes sense. But as almost every Fool knows, P/E ratios can be a bit of a facade. Have a look at the two companies' free cash flow instead.

Pepsi sells at a whopping 42% discount to Coca-Cola on an enterprise value-to-free cash flow basis. That lower free cash flow ratio means that you get more financial clout for less. You pay about the same for a dollar of earnings in both Coca-Cola and Pepsi, but you pay a whole lot less for each dollar of cash generated by the latter company.

Pepsi's cash flow growth shouldn't shrink anytime soon. Integration of the Quaker Oats unit is moving along faster than expected, and CEO Steve Reinemund has made it clear that he won't jump into a costly bidding war for European bottled water maker Danone. It looks like Pepsi will have more than enough free cash flow to fund about $2 billion of share buybacks this year.

Don't just take my word for it. Moody's (NYSE:MCO) is so pleased with Pepsi's cash flow that it bumped up its long-term debt rating a notch to Aa3 from A1. That puts Pepsi's long-term debt at the same level as -- you guessed it -- Coca-Cola's.

Compared to Coca-Cola, Pepsi looks like a bargain. In light of Pepsi's double-digit cash flow growth in the past year and its solid prospects ahead, don't be surprised if that deep discount narrows.

Have your own favorite in the cola wars? Tell us on the Pepsi discussion board.

Motley Fool contributor Ben McClure hails from the Great White North. Ben doesn't own any shares mentioned here.