Throw coffee + water into a big jar (~2 quarts), leave in the fridge for 12-hours. Filter, and you have ~1.7ish quarts of cold-brew coffee.
2-quart mason jars are like, $10 for a 6-pack.
https://www.walmart.com/ip/JARDEN-HOME-BRANDS-68100-Ball-6Pa...
Cold-brew in one Mason Jar, pour / filter into a 2nd jar. Heck, do 2 or 3 different flavors at once.
Get a pour-over filter holder (ceramic or glass works well in my experience):
https://www.target.com/p/melitta-sr-pour-over-cone-coffeemak...
And then get a bunch of Coffee Filters, usually $2 for ~100 of them. Bam. Cold Brew and its cheap as all heck too. Works on all kinds of coffee and tea in my experience.
Just batch it all up in one go, and you have enough coffee for the whole week. If you like it warm, put it in the microwave. The cold-brew process reduces the bitterness overall, so you get a different taste. But I prefer higher flavor and less bitterness that comes from the cold-brew process.
Nothing beats the convenience of cold brew. And you can use high-quality coffee with this method (K-Cups don't necessarily taste as good IMO. Less time for the coffee to infuse the flavor compared to traditional coffee making).
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Other tips:
1. Use a scale to measure coffee. Put the mason jar on the scale, and dump coffee into it until you reach your appropriate amount for your recipe. Somewhere in the order of 1-to-15 coffee-to-water ratio. (1750g of water to 120g of coffee. Varies per coffee you use however, so do it to taste). Water is 1-gram to 1-milliliter, 1kg to 1-liter. The Metric System is defined by the weight / volume of water, so its easy if you use Metric measurements. Scales are easier to use than measuring cups IMO. Scales mean fewer things to clean, while delivering more precision in measurements.
2. Mason Jars are standardized. Buy 3rd party caps, such as "Recap" (from https://www.recapmasonjars.com/ ) to make Mason Jars more usable. Both Wide-mouth and Standard-mouth jars are too wide in my experience, so "narrowing" the mouth with a Recap plastic top makes the pouring experience far better. The reason why I like Recap is because they use Rubber Gaskets to ensure a strong seal (a lot of random Amazon crap doesn't have a Gasket, and you get leaky coffee all over your pants if you use them).
3. Use high-quality filters to make the purest water possible. Coffee reacts to a lot of things in water, so its exceptionally important to filter as well as possible.