How to Pour Beer
If you're pouring beer from a bottle, can, or pitcher, tilt the glass at a 45-degree angle. Hold the beer 2 to 3 inches above the midpoint of the glass. Then, aiming for the center of the side of the glass, start pouring in a thick, steady stream. When the glass is 1/3 to 1/2 full, start leveling the glass so it's sitting flat right when you're done pouring. Let the foam, or "head," settle, then bottoms up!
Select a clean beer glass. This is usually a pint glass that is clear of all oils and dirt and that is appropriate for the style of beer to be poured. It should have no fingerprints, fuzz, dirt, or residue on the sides. If it does, it may taint the taste of your beer. There are glasses for virtually every style of beer; in lieu of a selected specialized glass, use a standard pint beer glass (16 oz. or 475 ml). This makes sure there is enough space in the glass for the entire beer and a bit of foamy head. If you’re pouring from a bottle or can, note the sediment at the bottom. Bottle-conditioned beers generally have a small layer of yeast on the bottom of the container that you probably want to avoid for taste (and clarity). If you have a bottle, raise it to the light to see if any sediment is visible. If you have a can, check the package for an indicator of sediment – the word “can-conditioned” is a dead giveaway. Some people like this taste, believing it makes the beer more pungent and that it gives the beer its true flavor. If you're not sure as to your preferences, try it out – only one way to know what you do and don't like, after all. Tilt the beer glass at a 45-degree angle. The edge of the glass should be resting on a flat surface, like a table, while the rest is in the air. This will help you balance the glass and keep everything even (and get the perfect aim for your pour). Position the beer container a few inches (several cm) above the midpoint of the glass. You will be aiming to pour the beer halfway up the glass. This is the best level for aeration and foam. Don't touch the bottle to the glass; this is just bad form. If it's yours it's no big deal, but if you're pouring for someone else, follow the etiquette of keeping the glass as clean as possible; there could be bacteria on the bottle, can, or pitcher. Begin pouring in a quick, steady stream. You want the beer to flow smoothly down the side of the glass without back-splash. Aim for the center of the side of the glass and keep the volume of the beer that's flowing as consistent as possible. Start to level the base of the beer glass when it is about one-third  to half full. You should level the glass at such a rate that the glass lies flat on the surface just when it becomes full with about one and a half inches (or 4 cm) of head at the top. As it fills up, you start setting it down. If too much head is starting to form, pour the beer in such a way that it does not touch the sides of the glass. This keeps it from aerating too much, keeping foam out of the equation. If not enough head is forming, keep the beer streaming down the side of the glass until you have an inch or two of foam. Wait a few seconds for the head to settle on the top of the beer before drinking. Take a sniff as soon as possible, however; the aromas are most pungent when the head is at its peak. It's now when you'll best get at the oak-y, citrus-y, or spicy flavors some beers claim. Be less aggressive with wheat beers and corked-bottle beers. You need to be a little gentler when pouring these types of beers; their head grows larger and faster than normal. A proper head is at least 1 inch thick, or two fingers deep, but not more. Take a beer like this slow and easy. For this type of beer, it may be advantageous to use a taller glass to allow for more foam. There's an entire art form when it comes to pouring wheat beers, and hard-core believers even roll the bottle around on the table before finishing the pour. Try swirling the last third of the beer while still in the bottle before finishing the pour in your glass. Watch out for dregs in bottle-conditioned beers. The last ½ inch or so in bottle-conditioned beers is generally no good, so leave it in the bottle. It's not that it's bad (though it can lead to a yeast-y flavor), it's just that it may cause excessive flatulence, or farting. However, some people prefer the richer, more bitter, concentrated yeast taste. If you are one of these people, pour away. Pour American Pale Lagers slowly. Beers like Budweiser and Miller are best poured slowly as in the steps above and down the side of a tilted glass. If you don't, they'll produce a glass full of head. While you do want some head for flavor and aroma, if it's all head, there's no beer. Because these beers have little protein, a big head will dissipate quickly, leaving a half-empty glass. Creating a big head slows the pouring process needlessly – and can be quite messy to boot. Use a double-pour when dealing with Guinness. Guinness aficionados swear by the two-part pour, or the double-pour method, for their beloved beer. This is where you pour the beer about ⅔ of the way up the glass and then wait for 30 seconds or so for the beer to settle (the nitrogen bubbles, technically). After that, fill 'er up to the brim of the glass – preferably a Guinness glass. Why is this important? Supposedly in creates the perfect amount of head and the best-tasting Guinness there is. If this is how they do it in Dublin, it's probably not a bad idea. Select a clean beer glass, usually a pint glass. It should be clear of all oils and dirt and is one that is appropriate for the style of beer to be poured (more on that in the 3rd section). If it was cleaned with chemicals, hold it up to the light to look for dirt and fuzz – glasses are best cleaned in hot water. There are glasses for virtually every style of beer; in lieu of a specialized glass, use a standard pint beer glass (16 oz. or 475 ml). Any smaller and it may not hold enough beer. Clear the tap line of excess pressure or old beer. Do this by running beer for a few seconds into another container. If you're dealing with pulls at a bar, just run a tiny bit into the drain before getting started – your beer-connoisseur customers will appreciate it. This will also give you a chance to see if the keg is running out, saving you from dirtying a glass and wasting time. Position the beer glass a few inches (several cm) under the tap at a 45-degree angle. You want the same angle under the tap as you would if you were pouring from a bottle or can. At this angle, the beer will hit the halfway up the glass, which is ideal. Don't touch the tap to the glass. Bacteria and germs can fester onto the end of any tap, making the glass contaminated if the two touch. If the beer isn't for you, follow proper etiquette just to be safe. Turn the tap all the way on so that beer flows quickly and steadily down the side of the glass. Some pulls will need to practically yanked, while others just need a nudge. Get it to a consistent stream and keep it there. Keep aiming for halfway up the glass until the stream hits beer organically. If head isn't forming, keep it on the side of the glass to allow for more air to produce foam. Level the beer glass slowly as it fills so that a layer of head about an inch and a half deep (about 4 cm) develops on the surface. Beer that is poured directly into the glass will not produce head; beer that is poured against the side the entire time will produce too much. To get into that sweet spot where the head is just the right size, start leveling the glass about halfway through the pour. If head is forming prematurely (as some beers do), move to pouring directly down the center of the glass. Fill it full! It's perfect when it seems like the head almost wants to spill over the side of the glass, but is kept in line by surface tension (technically lots of little bits of surface tension). Wait a few seconds for the head to settle on the top of the beer before drinking. But do take a sniff – when the head is in its full form is when the aromas are the strongest. It's at this point that you can smell the natural flavors of each beer and how they differ. 
Select a clean beer glass. If you’re pouring from a bottle or can, note the sediment at the bottom. Tilt the beer glass at a 45-degree angle. Position the beer container a few inches (several cm) above the midpoint of the glass. Begin pouring in a quick, steady stream. Start to level the base of the beer glass when it is about one-third  to half full. Wait a few seconds for the head to settle on the top of the beer before drinking. Be less aggressive with wheat beers and corked-bottle beers. Watch out for dregs in bottle-conditioned beers. Pour American Pale Lagers slowly. Use a double-pour when dealing with Guinness. Select a clean beer glass, usually a pint glass. Clear the tap line of excess pressure or old beer. Position the beer glass a few inches (several cm) under the tap at a 45-degree angle. Turn the tap all the way on so that beer flows quickly and steadily down the side of the glass. Level the beer glass slowly as it fills so that a layer of head about an inch and a half deep (about 4 cm) develops on the surface. Wait a few seconds for the head to settle on the top of the beer before drinking. 