You remember that rack of vanilla or pepper tequila infusions that used to be at every Portland bar? Those are almost all gone now. Housemade bar shrubs are also back in the weeds. You don't find many bartenders brewing their own beer, either.

But housemade cocktail bitters remain, the one bar trend that somehow will not fucking die.

That little eyedropper of Angostura aromatic bitters that makes your Old Fashioned old-fashioned was invented nearly 200 years ago by a German doctor in Trinidad, and it is perfect. The Peychaud's in your Sazerac has been unchanged since 1833, a blend of booze-soaked herbs and aromatics whose recipe is older than the oldest cocktail in the world.

But for some reason, a bartender who's been mixing drinks for three years figures, well, he's probably got a better idea. Have you tried the Herbsaint-mandarin-five-spice bitters he made last week in his garage? His buddy Austin says it's bomb.

Don't get us wrong—the Pearl District's ur-cocktail mecca Teardrop Lounge makes really good bitters, and it's been doing it for years. But even Teardrop does it only when it can't find a commercial bitters with suitable flavors.

"Things like dandelion leaf?" says Teardrop's Micah Ellis. "There's already a good version on the market."

But Belmont Street whiskey bar Circa 33 is not Teardrop Lounge, and it is most definitely not the House of Angostura. So what's with the "Old Fashioned" housemade bitters it debuted with a big ol' party two years ago? Why does Victory Bar need to have its own take on orange cardamom bitters? Who asked otherwise perfectly fine bar the Rambler to contribute a bitters blend to the pantheon?

The house bitters has jumped so many birch-scented sharks that even our local science museum is holding a bitters making workshop promising amateur fun with anise and cinchona.

The class will be held April Fools' Day. It is, of course, sold out.

To everyone but Teardrop Lounge and the Rum Club—who just make a single bitters, a falernum recipe that's no longer sold by Hale Pele's Blair Reynolds—I have a very personal plea. Stop it. Please. All of you. Stop it.

Most housemade bitters are bad.

I will use, as an example, a place I walk by near our newspaper's office that actually makes me cringe in post-aromatic stress response. It is called Solo Club, and it is a bitters-themed bar from the owners of Besaw's. The 7-month-old bar's main decorative feature is an entire wall of eyedroppers with labels in olde-tymey fonts. For $10, you can get three 4-ounce glasses of Portland Cider Co. semi-sweet cider with a different bitters in each pour.

Unfortunately, this is not a pleasant experience—not if you're grabbing house bitters. Solo's housemade grapefruit bitters is passable, if no better than grapefruit bitters available on the market. Its Cajun, meanwhile, is a mess of licoricey flavor with a peppery bite that catches unpleasant acid without pleasant heat. The hopped bitters is all mouth-sucking alpha acid, like a parody of what people hate about IPA applied to sweet cider: Portlandia through a shot glass and a bitters-dropped squeeze.

When you see how badly this goes, you come to understand why very few top-end bartenders in Portland make their own bitters by choice. Clyde Common's Jeffrey Morgenthaler mocks birch-bark bitters makers on his blog. Wayfinder's Jacob Grier says he leaves it to the pros. A bartender at Bible Club told me it's Icarus-caliber hubris.

"People have devoted their lives to making a consistent and balanced product," he told us. "It's the height of arrogance to think yours are going to be better after three batches."

Shift Drinks' Alise Moffatt carries three bitters—Peychaud's, Regan's and Angostura, a trinity that suffices for just about every classic cocktail in human existence.

"I think when something becomes a gimmick, a lot of bartenders want to jump on that gimmick," Moffatt says. "A bar will have strawberry-infused liquor, and those strawberries have been in that bottle forever. I'm not about to go to My Father's Place or Gil's Speakeasy and try their house bitters."

"They're looking for new whiz-bang things," says bitters maker Avery Glasser of Bittermens. "That's what gets the retweets. You have bartenders who feel pressure from ownership to make their own bitters."

Just as badly made house tonics make your stomach hurt—and stupid infusion ingredients like bacon can go rancid if you don't use them quickly—dumb ingredients in bitters can make you sick. You'll hear about bars that soak fruit pits without figuring out they're leaching cyanide, or soak cigars without realizing they're going to give you nicotinic heart palpitations.

"Calamus root or tonka bean can get a bar shut down," Glasser says. "One person stuck a cigar in some cognac, was drinking it, and he said it made his heart feel funny. I said, 'Did you stop drinking it?' He said he finished the bottle. I said, 'You're a fucking idiot."

Indeed.

The Bitters Making Workshop is at OMSI, 1945 SE Water Ave., 503-797-4000, omsi.edu, on Saturday, April 1. 11 am. Sold out.