Make some Dark Irish Soda Bread, and enjoy the benefits of what buttermilk can do for baked goods. (Julia Ewan/The Washington Post)

Got buttermilk? You might have questions about it — as in, why does it seem fine even weeks after its “use-by” date? Yours has been opened for a while, but can you freeze what’s left? Was it smart to buy the low-fat kind? And what are some good ways to use it?

Answers, in order:

● As long as your aged buttermilk smells like it did when it was fresh and looks creamy, it’s usable. Its tang and buttery notes are most likely diminished, but you can cook and bake with it. It has a low pH or level of acidity, which inhibits the growth of bad-for-you bacteria.

● Real buttermilk is naturally probiotic and low-fat — in the neighborhood of 0.5 to 1 percent. The kind labeled “low-fat” at the grocery store is a lesser product, made by introducing acidifying cultures into low-fat or nonfat pasteurized milk. In comparison, Kate’s creamery of Maine brand buttermilk begins as a byproduct of the company’s manufacture of butter, which is made from heavy cream. Buttermilk and yogurt cultures are added later.

● Yep, you can freeze the buttermilk you plan to use for baking. But that’s not ideal, because it will separate and need to be reincorporated.

Rustic Chocolate Chip Tea Bread from Lisa Yockelson, an easy and wonderfully aromatic weekend bake. (Deb Lindsey/For The Washington Post)

● The natural lecithin in buttermilk does wonders for baked goods, such as promoting a better rise and a more tender crumb. This being St. Patrick’s Day, an Irish soda bread would be just the ticket for using up a cup. We like this Dark Irish Soda Bread, rich with molasses and whole-wheat flour. Kentucky Buttermilk Cake and Rustic Chocolate Chip Tea Bread are personal b-milk favorites of mine. Ace baker and newly James Beard-nominated cookbook author Dorie Greenspan’s a buttermilk fan, btw.

Slaw With Pears, Toasted Hazelnuts and Buttermilk Dressing. (Deb Lindsey/For The Washington Post)

Our Recipe Finder’s chockablock with more buttermilk-friendly ideas, of course. That characteristic tang is highlighted in this Slaw With Pears, Toasted Hazelnuts and Buttermilk Dressing. The milk’s tenderizing effects are evident in a marinade; Definitive Fried Chicken is a perfect test case. For a lazy weekend breakfast (or Sunday night light meal), pour it into the batter for Cornmeal Waffles With Cheddar, Chipotle and Scallions, and your day will start off right.

I’m baking later today with February-dated buttermilk . . . will post the results online.

Top recipes of the week

As viewed by readers online:

(Deb Lindsey /For The Washington Post)

(Deb Lindsey /For The Washington Post)

1. ‘Dirty’ Cauliflower above, left. Ellie Krieger’s not all about “clean eating,” as this side dish with toasted bread crumbs shows.

2. Roasted Chile Lime Tofu Bowls above, right. An easy heap to assemble, from #WeeknightVegetarian.

3. Irish Coffee. This passes the Spirits column/M. Carrie Allan test, so we’re good with it.

4. Chicken Soup With Benefits. The annotated recipe guides you through from-scratch steps that lead to tender chicken, a faster broth and bonus fried chicken-skin garnishes.

5. Frozen ‘Irish Coffee.’ Inspired by the steamy heat of New Orleans.