Mason Jar Coffee

A mason jar is one of the simplest coffee brewers you can own: put coffee and water in, wait, and strain. It’s best known for cold brew, steeped overnight with the lid on, and it fits neatly in the fridge. With a cloth or paper filter stretched over the mouth, a jar can also make a hot cup, poured over like a pour-over. Here are two published cold brew recipes, the hot jar method, and how to keep the glass in one piece.

The short version

• Cold brew: 40 g of coarse coffee and 320 g of water in a 16 oz jar, steeped 12 to 24 hours.
• Coffee first, then water, then stir until everything’s wet.
• Strain through a sieve, cheesecloth or paper filter.
• Dilute with ice, milk or water: it’s a concentrate.
• For hot coffee, warm the jar first so the glass doesn’t crack.

How much coffee and water?

Two published recipes land on almost the same strength:

Recipe	Coffee	Water	Ratio	Steep
Pull & Pour	40 g, coarse	320 g, in a 16 oz jar	1:8	12 to 24 hours (18 preferred)
Starbucks at Home	4 tbsp (22 g) per cup, coarse	180 ml (6 fl oz) per cup	About 1:8	12 hours

Both make a concentrate. Pull & Pour explains that the strong 1:8 ratio lets you add ice or milk without the coffee tasting weak. For cold brew you can drink straight, it suggests 12:1 to 16:1 water to coffee instead. You can scale either recipe up or down to fit your jar.

Grind coarse. Pull & Pour says the long brew time would over-extract a finer grind.

How do you make cold brew in a mason jar?

This follows Pull & Pour’s recipe for a 16 oz jar:

1. Add 40 g of coarse coffee to the bottom of the jar.
2. Pour in 320 g of cold water, ideally filtered. Coffee first, water second: Pull & Pour finds it hard to mix the other way round.
3. Stir gently until no dry coffee sits on top.
4. Put the lid on lightly and leave it on the counter or in the fridge for 12 to 24 hours. Pull & Pour likes 18 hours, and suggests the full 24 if the jar is in the fridge.
5. Strain into a glass or a clean jar, through a sieve, cheesecloth or a coffee filter.
6. Add ice, milk or water to taste.

Starbucks at Home’s version covers the jar with cheesecloth held by a rubber band while it steeps, then strains through the cheesecloth into a jug after 12 hours. For a cleaner cup, I’d strain twice: once through a sieve for the bulk of the grounds, then through a paper filter for the fine silt.

Can you make hot coffee in a mason jar?

Yes, two ways.

Jar pour-over (Chowhound’s method). Hold a piece of cheesecloth or a coffee filter over the mouth of the jar with the jar’s ring or a rubber band, leaving enough slack to make a dip for the coffee. Put the grounds in the dip, pour hot water slowly over them, then lift off the ring, filter and grounds. Chowhound suggests a jar that holds about an 8 oz serving, and a medium or fine grind for this method.

Steep and strain. You can also treat the jar like a French press without the plunger: coarse coffee and hot water, steeped, then strained through a sieve or filter. I’d use the French press guide’s proportions, 30 g of coffee to 500 g of water, and strain it carefully, as there’s no mesh to hold the grounds back.

How do you stop the jar cracking?

Mason jars are thick glass, and Tasting Table explains why that’s a risk with hot water: glass conducts heat poorly, so the inside heats and expands before the outside does, and a big temperature gap can crack it. Thick glass is more vulnerable than thin glass, not less.

• Use a heat-rated jar, as Chowhound advises, and never one straight from the fridge.
• Warm it first with warm water.
• Pour slowly. Tasting Table suggests a metal spoon in the jar helps absorb some of the heat.
• Heat from cold, not suddenly. If you’re heating a jar in water, Tasting Table says to put it in the water first, then bring it to the boil.

General guidance only. Take care with hot water and glass, and stop using any jar that’s chipped or cracked.

How long does it keep?

Pull & Pour says mason jar cold brew keeps up to a week in the fridge; Chowhound says cold brew can last up to two weeks, and hot brewed coffee about three to four days. The jar’s lid makes it easy to store either way. I’d drink it within the week.

Mason jar coffee vs other methods

• Cold brew: the full guide to cold brew ratios, grind and every way to make it.
• Cold brew concentrate: strong cold brew made to dilute.
• French press: hot immersion brewing, with a mesh plunger to hold the grounds.
• Cowboy coffee: another no-gadget method, with a pot over the fire.

Explore every immersion method in the immersion chapter.