Hot trend Cramer wants you to watch

(Click for video linked to a searchable transcript of this Mad Money segment)

Cramer believes leveraging long-term themes is a shrewd way to invest. Especially if you get in early.

And the Mad Money host believes the rise of craft beer is a major trend that's sweeping not just the nation, but the entire globe.

According to the website run by the Brewer's Association, a craft beer is a beer made by a brewer who has either an all malt flagship or has at least 50% of its volume in either all malt beers or in beers which use adjuncts to enhance rather than lighten flavor.

"This is a real business—exports of craft beer soared 72% last year, and the markets in Canada, Brazil and Japan more than doubled.

And competition is growing at a rapid rate.

"Privately held Brooklyn Brewery, the company behind a craft beer called Brooklyn Lager, sold 176 thousand barrels of beer," Cramer said.

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The Mad Money find those results impressive, largely because the industry has been dominated by national companies such as Anheuser Busch Inbev for decades.

Of all the beer makers, Cramer said that Boston Beer has emerged as an important publicly traded company in the space. According to their website, founder and brewer, Jim Koch, brews Samuel Adams beers using the time-honored, traditional four-vessel brewing process and the world's finest all-natural ingredients.

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However, there's a valuable lesson to be learned as you're seeking to leverage a hot new theme. Just because a company is at the forefront of the trend doesn't necessarily mean it's a buy – at least not at current levels.

"My issue with Boston Beer is that the stock's already up over 50% year-to-date, and it's now trading at 34 times next year's earnings estimates. Although I think Boston Beer is a terrific company, the valuation is extremely stretched. At these levels I'd ring the register," Cramer said.

In the meantime, keep an eye on the stock and the trend. Sometimes when a theme is in its early stages the best thing to do is watch – and wait.

Call Cramer: 1-800-743-CNBC

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