Yesterday, CNBC's Herb Greenberg and Jim Cramer did a taste-test comparing soda from SodaStream's (Nasdaq: SODA) do-it-yourself machine to a can of soda from Coca-Cola (NYSE: KO). Cramer has been a very vocal SodaStream bull -- is he ever not vocal, really? -- while Greenberg has been skeptical of both the company and the stock.

The verdict? In the blind taste test, both Greenberg and Cramer chose the SodaStream pop both times. (You can watch the video here).

A comment that Greenberg posted on Twitter afterward particularly piqued my interest:

Let me just say, in all seriousness re the $soda challenge: beyond the blindfolds/fun it's actually research every investor should do.

Classic Lynch
Peter Lynch is the anointed godfather of "Buy what you know" investing, which stems from his classic One Up on Wall Street. Personally, I have a bit of a love/hate relationship with "Buy what you know" investing, simply because it can very easy to morph into "Buy without doing much research" investing.

Of course, there's also the question of individual taste. Just because you don’t like something doesn't mean that hordes of other people won't love it. For instance, if I'm on the road back East, I'd much rather sit down for an Old Timer's breakfast at Cracker Barrel (Nasdaq: CBRL) than grab food from McDonald’s (NYSE: MCD). However, McDonald's as an investment has a lot more going for it -- better run, better brand, broader reach -- than Cracker Barrel.

McDonald's stock has left Cracker Barrel's in the dust over the past five years. In that light, I'm very glad that I don't let my taste buds completely rule my investments.

In addition, knowing and liking a product doesn't eliminate the possibility that the product is a fad, or that the company is horribly ill-managed. I previously wrote about the disaster that is American Apparel (AMEX: APP) when it comes to the management issue, and Crocs (Nasdaq: CROX) is an easy target on both the fad and management fronts.

Much love for Herb
I'm not trying to pick on Herb Greenberg here -- I actually am a fan of his, and I know that he was simply noting that such a taste test is a good idea as part of the research process. If you're going to sink your hard-earned investment dollars into a company like SodaStream, you probably ought to give the product a test run.

Instead, I figured Greenberg's quick-fire thought should remind Fools that just because you enjoy SodaStream soda, Starbucks coffee, or Chipotle burritos, that preference alone is not nearly enough of a justification to sink your investment dollars into the stock. For Foolish investors, it can be a good start -- but after that, it's time to get your hands dirty with further research.