"Milkshake," "smoothie" and "pastry" are words that are increasingly appearing on beer menus. Cloudy, sweet, often fruity with a creamy mouthfeel, these dessert-like brews are the latest hot trend in beer. But what are they?

Nearly all of these beers use lactose — a milk sugar — as an ingredient.

Lactose adds a touch of mild sweetness to a beer's profile, but its main contribution is in the mouthfeel. It is at least partly responsible for the rich body and creamy smoothness of many milkshake beers. The use of lactose in brewing is nothing new. Milk stout — also known as cream stout or sweet stout — first appeared in England in the late 19th century.

Milk stout's popularity in England waned in the mid-20th-century, but the style was revived in the 1990s by American craft brewers. While not as thick as some milkshake beers, it does exhibit the creamy mouthfeel associated with lactose.

Taste the difference

If you want to taste this throwback style, Left Hand Brewing in Longmont, Colo., makes a great one. It is available bottled with both nitrogen carbonation and the normal CO2. Flavors of coffee and bitter chocolate are present in both, but Milk Stout Nitro pushes the chocolate far to the front, while the Milk Stout CO2 version favors coffee. Acrid, roasted malt character is more apparent in the CO2 version. The nitro comes off sweeter. Milk Stout Nitro gives the impression of a soft, comforting blanket compared with the edgier profile of the other. Each is delicious in its own way.

Lactose is not the only ingredient that defines a milkshake beer. Oats are often a part of the mix, bringing additional smoothness and contributing a bit of haze. Vanilla is common, giving these beers a custard-like sweetness. Many contain fruit, contributing both flavor and pectin-derived cloudiness. Almost any baked-good inspired ingredient can be added, including marshmallows, graham crackers, coconut, cocoa and caramel. Milkshake beers tend to be like dessert in a glass.

While pastry stouts and lactose porters are popular, brewers today are pushing beyond those dusky brews. Virtually any style can be turned into a smoothie, even IPA and sour beers.

Think dark chocolate

If you want to dip a toe into milkshake and pastry beers while staying somewhat traditional, try Cookies & Cream Milk Stout from Waconia Brewing Co. Think of those chocolate chunk cookies that grace the spread at nearly every catered event and you have nailed the flavor of this beer. The impact of chocolate is huge — both cookie and bitter dark chocolate chunks. It's a sweet beer to be sure, but a subtle hint of roasted malt helps cut that a little. The texture is creamy smooth. While I quite enjoyed this beer, a full 16-ounce can is too much of a good thing. Find a friend and share.

Sticking with stouts, this year's FSB Imperial Stout from Fair State Brewing Co. comes in three versions, all of them full-on pastries. In fact, they were brewed in collaboration with Austin Jevne, head brewer at Forager Brewery in Rochester, who is well known in the state for his pastry beers. At 13% alcohol, these are all big beers and super-rich. A little will go a long way.

The salted caramel stout is the only version that contains lactose, and it's also the best of the three. It's like a chocolate-covered caramel sprinkled with sea salt. The caramel comes through clearly, as does the salt, though it's not overly salty. This one seems less sticky sweet than the others, a pleasant, if intense, sipper.

The macaroon-inspired version is brewed with coconut, vanilla and chocolate. It delivers what it promises — a gooey coconut macaroon in a can. Coconut and chocolate manage somehow to cut through the overwhelming sweetness. The mouthfeel is nearly viscous. If you're a fan of sweet desserts, this one might be for you. I found it to be too much to take, and an ounce or two was plenty.

I had a similar response to the s'mores-inspired stout. Extremely sweet and brewed with graham cracker, marshmallows, cocoa nib, honey and vanilla, it does indeed taste like that campfire treat. But whereas s'mores are already too much for me, this beer pushes that experience well over the top.

Beginning with IPA

On the opposite end of the style spectrum from big, sweet stouts is the milkshake IPA. This one is a bit of an oxymoron. India pale ale is by definition a bitter and refreshing beer loaded with typically fruity hop aromas. Milkshake IPAs start with the already less bitter New-England-style IPA and then add sweetness with the addition of lactose and sometimes vanilla. Perhaps brewers should find another name for the style, but IPA sells.

Shook from Modist Brewing in Minneapolis is perhaps the best known of the local lactose IPAs. Shook Double Vanilla starts with huge tropical fruit, pineapple and citrus hop aromas that carry over into the flavor. Low bitterness combines with vanilla to make it seem sweeter than it really is. The vanilla lingers well into the finish. The image that came to mind while tasting this beer was cake batter — an unbaked pineapple upside-down cake.

For something that stays truer to the IPA style, try Crackin' Skulls from Fargo's Drekker Brewing Co. Lactose serves more to enhance body and smoothness than to add sweetness. Both the aroma and the flavor are all hops. Juicy pineapple and mango dominate the profile with a touch of lemon peel for contrast. It's a touch sweeter than many straight IPAs, but the bitterness is sturdy enough to keep it at least somewhat balanced. Oats and lactose give it a fuller body than most New England IPAs.

Pastry sour beer is another category that defies expectations. The base is a tart, kettle-soured beer, which is then sweetened up with lactose and often vanilla. In the most extreme examples, the sourness is relegated to an afterthought. The better ones display a delicate sweet-and-sour balance.

Berryz Puff Tart from the Brewing Projekt in Eau Claire, Wis., leans more toward the sour side. It is a berry explosion from the minute the beer is poured. Strong smells of raspberry, blackberry and blueberry waft up from the glass. All three berry varieties stand out on the tongue. The lactose doesn't sweeten the beer to any significant degree, but it does add smoothness to the mouthfeel. Vanilla is subtle on the palate, but comes in strong for a custard-like finish.

Michael Agnew is a certified cicerone (beer-world version of sommelier) and owner of A Perfect Pint. He conducts private and corporate beer tasting events in the Twin Cities, and can be reached at michael@aperfectpint.net.