I call it the Guinness effect — that moment you receive a nitro beer, stare at the incredibly thick, creamy head and become mesmerized by the slowly cascading bubbles. Nitro beers are alluring in appearance, but also in their silky smooth taste.

Guinness perfected the process of adding nitrogen to beer in 1959. Up until then, this beer was traditionally carbonated in casks and carefully poured at the bar. It took Guinness another 30 years to develop a way to package its world famous nitro stout into a bottle, through the invention of the widget (that tiny ball you hear rattling around a Guinness can or bottle).

For many years, if you wanted to enjoy a nitro beer you were limited to Guinness and a few other Irish and English brands, or you had to visit a pub that served beer on nitro.

With the growth of craft breweries in America, more and more nitro beers have been produced for serving on draft. The process of getting those nitros into bottles or cans, however, has been extremely difficult and expensive, because Guinness owned many of the patents on its widget system. American brewers have had to get innovative and figure out a new way to package nitro beers without a widget. Many credit Colorado-based Left Hand brewing with being the first to release a “forced nitro” beer in a bottle in 2011.

WHAT MAKES nitro so appealing, especially for darker, maltier beers? Nitrogen bubbles are less likely to diffuse out of the beer because the atmosphere that we breathe is 80 percent nitrogen and 20 percent oxygen. Those tiny nitrogen bubbles create a persistent foamy head and lend that trademark creamy texture while softening some of the more robust flavors from hops and darker roasted malts.

On the other hand, carbon dioxide produces large bubbles that try to escape to the surface, carrying with them aroma, and creating a prickly, acidic flavor and sting on the tongue that intensifies the flavor of the beer.

Many of today’s craft breweries are starting to release their own versions of “forced nitro” beers in bottles and cans. It has taken many breweries years to perfect the packaging process to ensure that when you crack open that can you get a perfect creamy pour.

But be aware, these forced beers must be poured in a very specific way to achieve their full effect. Left Hand Brewing termed the technique the “hard pour,” and few customers are aware of it.

Here are a few pointers on how to get it right:

>> Always pour into a glass. Drink straight from the bottle or can and you won’t get that thick creamy head or smooth taste. The nitrogen needs to be released by pouring into a big enough vessel. For a 12-ounce beer you’ll want at least a 14-ounce glass.

>> Before opening the bottle or can, gently turn it over two or three times to make sure the nitrogen is properly distributed.

>> Open and immediately pour into the center of the glass with the bottle or can completely inverted. Do not try to pour gently down the side as you would a normal beer. Pour “hard” upside down and let the beer gush out and splash around in the glass.

>> Sit back and enjoy the show. A thick, dense and creamy tan head will form, with tiny bubbles rising from the bottom of the glass. Let the head settle for a moment, then enjoy.

It is important to pour this way or you will be left with a dead, lifeless beer with no head and very little creaminess in texture. Unfortunately, many beer makers do a poor job of instructing customers on the hard pour — but now you know.

NOW IT’S time to seek out a few great nitro beers to enjoy at home.

>> Modern Times City of the Dead Nitro comes in a 16-ounce can and is brewed with bourbon barrel-aged coffee, cacao nibs, almonds and a touch of sea salt. The coffee beans are actually aged in used bourbon barrels, giving them a touch of sweet, oaky caramel flavor. Tastes of Almond Roca and espresso dominate with a smooth, velvety finish.

>> Not all nitro beers are stouts. Petrus Nitro Quad is a quadrupel, or strong Belgian-style ale, that benefits from the soft texture of nitrogen and comes in 11.2-ounce bottles. This is a rich and malty beer with aromas and flavors of chocolate, dark caramel nougat, dark fruits and a touch of clove spice. The thick whipped head and smooth finish hide this beer’s very high alcohol-by-volume content (11.2 percent) incredibly well.

>> Firestone Walker’s Nitro Merlin Milk Stout could easily be downed with breakfast or dessert. Available in 12-ounce cans in six-packs, this slightly sweet stout has notes of milk chocolate, lightly roasted coffee and sweet cream. Pair with a malasada in the morning or a shortbread cookie in the evening for a magical combination.

Tim Golden, a certified cicerone, shares his obsession with all things craft beer monthly. See his blog, “Beer in Hawaii,” at beerinhawaii.com.