A Massachusetts mayor has taken a pledge of sobriety — at least when it comes to Samuel Adams brews — after the beer company’s co-founder Jim Koch praised President Trump for his contentious tax cuts.

Somerville Mayor Joseph Curtatone, a Democrat, made a sobering declaration Sunday on Twitter: “I will never drink Sam Adam’s beer again!

No more Winter Lager.

No more Summer Ale.

No more Rebel Grapefruit IPA — sigh.

It all started when Koch, co-founder and chairman of the Boston Beer Co., which produces Samuel Adams, met with the president.

The Boston Business Journal reported that Koch and a dozen other corporate executives joined Trump for dinner Aug. 7 at his golf club in Bedminster, N.J., to talk about their businesses and the larger economy — and, during the meal, Koch expressed his appreciation for the Republican tax cuts that, he said, will help his own business.

“I’m Jim Koch, and I started making Sam Adams beer in my kitchen 37 years ago,” he said, according to a transcript from the White House.

“When I started Sam Adams,” Koch added, “American beer was a joke and it p‑‑‑‑d me off. And now, American brewers make the best beer in the world. And the tax reform was a very big deal for all of us, because 85 percent of the beer made in the United States is owned by foreign companies.”

“That’s right,” Trump said.

Koch: “I mean, Americans — I’m the largest American-owned brewery at 2 percent market share. We were paying 38 percent taxes —”

Trump:  “Wow. But you’ve done a great job. Great job.”

Koch: “— and competing against people who were paying 20. And now we have a level playing field.”

Then Trump said: “Yeah. That’s good. We’ve done that. That was a very unfair situation. That’s right. Good job. That’s a really good job.”

When Somerville’s mayor got wind of Koch’s remarks, he got all hopped-up and threatened to boycott the business executive’s beer.

“We need to hold these complicit profiteers of Trump’s white nationalist agenda accountable,” he tweeted.

Then he addressed Koch:

Boston Beer and the mayor’s office did not immediately respond to requests for comment.

However, the Internet had plenty to say — and some of it was comical.

Though some people on social media supported Curtatone, many were more critical of the mayor’s stance.