When I used to work fast food, my manager told me that the most expensive component of a soft drink is the ice. Syrup & (filtered) water are pennies, but ice requires electricity to maintain and it’s a little more expensive than you’d think.

Another commenter suggested cold brew. That’s probably the best to maximize sweetness. Good luck!

If I were to provide a suggestion, I would start with fresh grinding your coffee from beans. You can get a pretty cheap manual grinder for like $20-30. I don’t remember the name of mine (it’s generic) but it was like $30 on Amazon and is great when I travel.

Next time you’re in a coffee shop, grab their cheapest blend. Coffee shops, in my experience, have fresher beans than the grocery store, especially if they roast their own coffee.

It doesn’t have to be the $26 organic single origin, just something that’s been roasted more recently than 6 months ago. Maybe you’ll be able to convince your S/O to get some better coffee in the future.

Honestly, your ingredients are going to far surpass any brewing method. I’ve brewed cheap coffee in my Chemex that didn’t taste very good and quality coffee in a hotel in-room Coffee machine that tasted amazing.

Good Beans + Good Water gets you like 70% of the way to good coffee.