If your beer tastes like cardboard, you might want to reconsider drinking it.
It was probably stored in a heated room, which accelerated the oxidation process, creating that flat, wet paper flavour.
If you crack a bottle of your buddy’s homebrew and have to wrap your lips around the end of the bottle to staunch the entropy of overcarbonation… and it smells like cider, and feels like acid eating away at your tongue… then you have plenty of reason not to finish the bottle, without apologies.
This could be contamination due to lack of good sanitary practices during the brewing process, or it might be the result of extremely active yeast that eats everything in sight and produces bitingly high levels of carbon dioxide.
This is especially true with the dried yeast you get in beer kits.
I started brewing in the mid-1990s with home brew kits. Easy cheesy. Pour malt extract syrup and corn sugar in pot. Add water. (Drink beer.) Boil. Pour into glass carboy (the fermenting vessel) and top up with cold water.
Add yeast. (Drink beer.) Ferment. (Drink many beers over the course of a week.) Transfer to second carboy. (Drink more beer.) Bottle. Wait… and finally drink one of your new creations.
In those early days, my homebrew always tasted dry and cidery. One culprit was the yeast; the other was the addition of corn sugar to the brew pot. This is like crack to yeast—a high octane feeding-frenzy fuel.
Corn sugar will entirely convert to ethanol. The more you add, the less your beer tastes like beer, and the more it tastes like… uhm, Zima?
Every once in a while at a homebrew competition, a beer gets cracked to be judged and shoots a beery geyser into the white stucco ceilings.
Invariably, it will be a jet black chocolate stout and you will be wearing your favourite beer shirt and it will be christened with the foul, unholy spray.
When everything settles there is an ounce of beer in the bottle and it tastes like smoky Listerine… You probably don’t want to drink this.
Those flavours are the bad kind of phenols (unlike the good spicy phenols in Belgian beers), caused by contamination, that make the beer taste harsh and medicinal. You’ll find this is more common in homebrewed rather than commercial beer.
Again, just put the beer down and walk away. Life is too short to drink crappy beer.
Sometimes beer tastes metallic. In homebrew it can be caused by brewing with well water with high iron content. In commercial beers, it can be a product of oxidation factor that will dissipate by decanting the beer into a glass and letting it breathe.
Every once in a while you get a beer where the metallic character persists. This may be caused by the breakdown of the thin plastic coating on the inside of the metal crown of the bottle, and any beer in contact with the bottle cap can theoretically leach iron from the bottle cap.
Call me anal, but I will entirely rearrange the contents of my fridge to keep my six packs upright.
The Amazonian people have their own indigenous fermented beverage distantly related to beer: chicha.
The women sit around in a circle chewing wads of cassava and spitting the resulting juice into a big communal pot. The enzymes from the mouth convert the cassava starches in the pot to sugar.
The spittle-sugar mix gets mixed with water, wild yeast lands in the pot, and the whole thing starts to ferment.
I haven’t spent much time in the Amazon, so I haven’t stumbled upon this beverage, but I have read accounts that say it tastes harsh, alcoholic and yeasty, which actually sounds a lot better than drinking spit.
You may, at some point during your travels, be handed something that looks like beer but smells like a barnyard and tastes like sour fruit and funk: Belgian lambic.
Even though wild sour lambic beers have been brewed for hundreds of years in Belgium, it doesn’t mean you have to like them.
By the same token, just because Anheuser-Busch has spent millions of dollars trying to convince people that Budweiser mixed with tomato juice and squeezed clams (Chelada) is the best thirst quencher doesn’t mean anybody has to agree.
The line between ambrosia and oral offensiveness sometimes gets a little blurry.