I tried 7 brands of cold-brew concentrate to find the best one, and there was a clear winner

Each bottle I tried suggested doing a ratio that's equal parts cold-brew concentrate to water (or milk).

So, for example, if the bottle had 32 ounces of coffee in it, then it would make 64 ounces of beverage, or eight 8-ounce drinks. This made it a bit easier for me to compare costs.

To taste each variety, I made a drink with a 1:1 ratio of concentrate to water. Here's my final cold-brew ranking, from my least favorite to my top pick.

The only coffee concentrate I could find from Walmart's Great Value label was the donut-shop medium roast.

It came in a 32-ounce plastic bottle for $4.42, making it $0.14 per ounce. This coffee was the cheapest, but it was also my least favorite.

I expected that specific, lightly sweet flavor that's often associated with the "donut shop" descriptor. Or, I guess I expected some flavor at all.

In all honesty, I think this tasted like water with a little bit of coffee in it, and the consistency was super thin.

I was disappointed, but the good thing about cold-brew concentrate is that you can control how much of it you use based on your personal preference. This brew might taste better if you ignore the suggested 1:1 ratio and use way more concentrate than water.

This brew was also from a Walmart private label — though Bettergoods is considered a bit more premium and trendy than Great Value.

A 32-ounce bottle of Bettergoods' cold-brew black coffee concentrate cost me $5.96 — or $0.19 per ounce.

This had a bolder, richer taste than the Great Value option, as though it has been brewed longer. However, it still had that displeasingly similar thin, watery consistency.

Target's Good & Gather cold-brew concentrate is basic unsweetened black coffee, served in a very similar plastic bottle to the ones from Walmart.

The 32-ounce bottle cost me $6.39, or $0.20 per ounce.

This coffee had more of a red color to it than the others. It seemed very similar in flavor to the Bettergoods option, though slightly thicker.

The medium-roast brew felt pretty mild and smooth. I wasn't blown away, but I think this brew would pair nicely with a bit of cream.

The Dunkin' cold-brew concentrate came in a 31-ounce bottle that cost me $8.59, or $0.28 per ounce.

After I mixed my water with the concentrate, I noticed the coffee almost had an oily consistency. It reminded me of some of the drinks I get at Dunkin' locations, and I didn't care for it.

(In my experience, adding a splash of milk makes this consistency less noticeable — but this isn't helpful if you drink black coffee.)

This brew was the lightest in color, and I'd probably describe it as weak with a slightly bitter aftertaste. Still, it wasn't bad.

Chameleon's organic "super" cold-brew concentrate came in a 32-ounce glass bottle for $8.99, or $0.28 per ounce.

The flavor was bolder and more satisfying than the other brews I tried. However, as someone who likes a little sugar in her drink, I still made a face at the strong aftertaste.

This coffee tasted the strongest and the most bitter of the ones I tried, but this could be easily balanced with a touch of sugar and creamer.

Chameleon's "super" cold brew may not best option for a smooth morning beverage if you prefer a milder black coffee drink.

A 32-ounce bottle of Starbucks signature black cold-brew concentrate cost me $7.98, or $0.25 per ounce.

Price-wise, this was a decent middle-of-the-road option. Taste-wise, I could easily see this brew appealing to the masses.

I didn't feel the need to add cream or sugar to this cold brew because it tasted so mild. The aftertaste was pleasant, and the coffee tasted less bitter than most others I tried.

It was enjoyable on its own, and it blended really smoothly with cream when I tried it again later.

The cold-brew concentrate from Stumptown Coffee Roasters came in the prettiest 25.4-ounce glass bottle.

It was the most expensive brew I tried by far at $12.99, or $0.51 per ounce. Unfortunately, it also happened to be my favorite.

The coffee had a thicker consistency than others, plus a bold flavor without a bitter or unsatisfying aftertaste. In my opinion, this was the best cold brew to drink black.