Mason Jar Coffee: How to Make Cold Brew in a Mason Jar (and Iced Coffee)
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The humble canning jar has become one of the most useful pieces of coffee gear in the kitchen. It measures, steeps, shakes, stores and even serves. If you want to know how to make cold brew in a mason jar, it is this simple: put coarse coffee in a quart jar, fill with cold water, stir, close the lid and leave it in the fridge for 12–18 hours. Then strain it through a paper filter or a fine sieve back into a clean jar. No cold brew maker needed.
Below you will find exact amounts for pint and quart jars, three straining methods, a shaken iced latte made in the same jar, and the storage and glass-safety details that matter.
Key takeaways
- Use a coarse grind and cold, filtered water.
- For concentrate, use about 1 part coffee to 5 parts water by weight; for ready-to-drink cold brew, about 1:10.
- Steep 12–18 hours in the fridge, then strain twice for a clean cup.
- Wide-mouth jars are easier to fill, stir and strain.
- Never shake hot coffee in a sealed jar.
In this article
- Why a mason jar works so well
- How to make cold brew in a mason jar
- Three ways to strain
- Shaken iced latte in a jar
- Storage and safety
- FAQ
Why a mason jar works so well
Mason jars were designed for home canning: thick glass, a threaded neck and a lid that seals tightly. John Landis Mason, a New Jersey tinsmith, patented his screw-threaded jar in 1858, and old jars embossed “Mason’s Patent November 28th 1858” are still collected today. For coffee, those same features are useful:
- Airtight lid: keeps cold brew from picking up fridge odors.
- Glass: does not hold onto old coffee flavors the way some plastic can.
- Standard sizes: pints and quarts make the math easy.
- Measuring marks: many jars have ounce and milliliter lines on the side.
Jars come with two mouth sizes: regular (2⅜ in / 60 mm) and wide (3 in / 76 mm). Choose wide-mouth for coffee: it is much easier to pour grounds in and scrape them out.
How to make cold brew in a mason jar
Amounts by jar size
| Jar | Style | Coarse coffee | Cold water | Approx. yield |
|---|---|---|---|---|
| Pint (16 oz / 473 ml) | Concentrate (1:5) | 2 oz (60 g), about ¾ cup | 1¼ cups (300 ml) | about ¾ cup concentrate |
| Pint (16 oz / 473 ml) | Ready to drink (1:10) | 1¼ oz (35 g), about ½ cup | 1½ cups (350 ml) | about 1¼ cups |
| Quart (32 oz / 946 ml) | Concentrate (1:5) | 3½ oz (100 g), about 1¼ cups | 2 cups + 2 tbsp (500 ml) | about 1¼ cups concentrate |
| Quart (32 oz / 946 ml) | Ready to drink (1:10) | 2¼ oz (65 g), about ¾ cup | 2¾ cups (650 ml) | about 2¼ cups |
Cup measures for ground coffee are approximate; a kitchen scale is more accurate. The grounds take up space and absorb water (roughly twice their weight), so these amounts leave headroom in the jar and you get back less liquid than you put in.
Steps
- Add the coffee. Put the coarse ground coffee in a clean jar. Coarse matters: fine coffee makes cold brew muddy and hard to strain.
- Add half the water and stir. Pour in about half the cold, filtered water and stir with a long spoon until there are no dry pockets.
- Top up. Add the rest of the water, stir once more and close the lid.
- Steep in the fridge for 12–18 hours. Around 14–16 hours suits most coffees: shorter is lighter, longer is stronger and more bitter.
- Strain using one of the methods below, into a second clean jar.
- Serve. Dilute concentrate about 1:1 with water or milk over ice; serve ready-to-drink cold brew as is.
For the general method and troubleshooting, see our full guide on how to make cold brew. If your batch comes out off, cold brew bitter or weak has the fixes.
Three ways to strain mason jar cold brew
| Method | How | Result |
|---|---|---|
| Sieve plus paper filter | Pour through a fine sieve, then again through a paper coffee filter set in a funnel or dripper | Cleanest, sediment-free; slow second pass |
| Nut milk bag or cloth | Line a funnel or bowl with the bag, pour, then lift and let drain without squeezing | Fast and clean; rinse the bag well after use |
| Mesh jar insert | Steep the coffee inside a mesh cold brew insert that fits the jar, then lift it out | Easiest; a little fine sediment, so add a paper filter pass if you like |
Tip: let the jar stand for 10 minutes after steeping. The grounds sink, and you can pour most of the coffee off the top before the bottom layer clogs your filter.
Shaken iced latte in a jar
The same jar makes a frothy iced coffee in under a minute.
- Fill a pint jar halfway with ice.
- Add ½ cup (120 ml) cold brew concentrate, or a double espresso that has cooled for a few minutes over a couple of ice cubes.
- Add 1–2 teaspoons syrup and ½ cup (120 ml) cold milk.
- Close the lid tightly and shake hard for 15–20 seconds.
- Drink straight from the jar or pour into a glass. The shaking creates a light foam, a trick borrowed from the Italian caffè shakerato.
For a make-ahead breakfast, combine concentrate, milk and syrup in a jar the night before and keep it in the fridge; just shake with ice in the morning.
Storage and safety
- Keep it cold and sealed. Strained cold brew in a clean, closed jar keeps best in the fridge; most people find it tastes best within about a week. See how long cold brew lasts.
- Add milk only when serving. Milk shortens the shelf life of any coffee drink.
- Do not shake hot liquids in a closed jar. Steam builds pressure and the lid can pop off. Cool hot coffee over a few ice cubes first.
- Avoid sudden temperature swings. Do not pour boiling water into a jar straight from the fridge, or put a hot jar on a cold, wet surface. Glass can crack.
- Check for chips. Discard jars with chipped rims or cracks.
- Clean promptly. Coffee oils turn rancid; wash jars and lids in hot soapy water after each batch.
Which coffee to use
Cold brew highlights chocolate, caramel and nutty flavors and mutes acidity, so medium-dark and dark roasts are easy winners. Feel Espresso’s Cold Brew Coffee is a dark French roast blend that comes coarse ground specifically for cold brew, smooth and naturally sweet. Brazil Santos, with cocoa and roasted nuts, makes a mellow jar of cold brew, and Mexican Chocolate adds cocoa, cinnamon and vanilla for a dessert-like glass. Choose the Coarse grind when you order ground coffee.
Mason jar coffee FAQ
How much coffee do I put in a quart mason jar for cold brew?
About 100 g (roughly 1¼ cups) of coarse coffee with 500 ml (2 cups + 2 tbsp) of water for a concentrate, or 65 g with 650 ml for ready-to-drink cold brew. That leaves room for the grounds without overflowing.
Can I leave cold brew on the counter instead of the fridge?
Cold brew steeps faster at room temperature, about 12 hours, but the fridge is the safer choice for food safety and gives a cleaner flavor. Once strained, always refrigerate it.
Can I pour hot coffee into a mason jar?
Canning jars are made to handle heat, but avoid sudden temperature changes. Warm the jar with hot tap water first, and never seal and shake hot coffee.
Why is my mason jar cold brew cloudy?
Fine particles from a grind that is too fine or a single coarse straining. Strain a second time through a paper filter.
Can I make hot coffee in a mason jar?
You can steep it like a French press, but a jar does not hold heat well. For hot coffee, a French press is a better tool.
Sources
- Mason jar, Wikipedia (history, patent and jar sizes).
Facts checked in October 2026.
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