Cold Brew Coffee: How To Make Cold Brew at Home, Ratios 101

Ever pour iced coffee that tastes thin and a little harsh? That’s hot-brewed coffee meeting a mountain of ice. Cold brew is different, but the internet can make it feel complicated—mysterious ratios, gadgets, conflicting steep times. You want a smooth, chocolatey cup you can repeat every week without fuss, whether you’re brewing for one glass or a fridge-friendly batch.

Good news: great cold brew is easy and forgiving. With a jar, a French press, or a simple brewer, you can steep coarsely ground, freshly roasted coffee in cool water to make a low-acid concentrate that stays tasty for days. Nail the coffee-to-water ratio once, and you’ll customize every cup to your taste.

In this guide, we’ll cover what cold brew is (and isn’t), the gear that helps, which beans and grind to use, foolproof ratios for concentrate vs ready-to-drink, steep time and temperature, clean straining, dilution, serving ideas, flavor upgrades, scaling, storage, troubleshooting, and pro tips. We’ll also share Fat Frank Coffee picks that shine on ice. Ready to brew better?

Step 1. Know what cold brew is (and isn’t): cold brew vs. iced coffee

Cold brew isn’t just coffee with ice. It’s coffee steeped in cold or room‑temperature water for 12–24 hours, then strained into a smooth, low‑acid concentrate. Iced coffee, by contrast, is hot‑brewed coffee that’s cooled and poured over ice. The method—not the temperature in your cup—is what changes flavor, body, and bitterness. You can drink cold brew over ice or even warm the concentrate for a mellow hot cup; it will still taste rounder than hot‑brewed coffee.

• Water temperature: Cold brew uses cool water; iced coffee starts hot.
• Time: Cold brew steeps slowly (about 12–24 hours); iced coffee is brewed in minutes.
• Flavor: Cold brew is smoother/less bitter; iced coffee can taste sharper and more diluted over ice.

Step 2. Choose your method and equipment (mason jar, French press, or brewer)

Your gear sets the tone for how hands-on you want to be. The good news: each method below can deliver smooth, consistent results when you’re learning how to make cold brew—just match the tool to your preferred cleanup and clarity.

• Mason jar: Budget-friendly and reliable. Steep in a 24–32 oz jar with a lid, then strain through a fine-mesh sieve lined with cheesecloth or paper filters. Double-filter for extra clarity. Great for small to medium batches.
• French press: Built-in filter makes brewing and decanting simple. Press to separate grounds, then optionally pour through a paper or cloth filter to remove fine silt. Easy pour spout, minimal extra equipment.
• Dedicated cold brew brewer: Reusable filter baskets and a tidy drain/stopper make larger batches easy and less messy. Follow the maker’s ratio and steep-time guidance; you’ll still strain once for a clean concentrate.

Whichever route you choose, cover the brew while it steeps and plan a thorough strain for grit-free sipping.

Step 3. Pick your beans and grind size (freshly roasted, coarse grind)

Start with beans you actually love—there’s no single “best roast” for cold brew, so choose your favorite. What matters most is freshness and grind. Grinding right before steeping keeps aromatic oils intact for fuller flavor, while a coarse grind helps you extract smoothly without bitterness. Think “easy to strain, never sludgy,” and you’re on the right track for how to make cold brew that’s clean and consistent.

• Go fresh, grind fresh: Freshly ground beans = brighter, more complex cups than pre-ground.
• Grind coarse (coarse cornmeal): Too fine can over‑extract and make your brew muddy and gritty.
• Using pre‑ground? It works—steep on the shorter end and plan to double‑filter for clarity.
• No grinder? Have the beans ground coarsely at the shop or use a store grinder set to coarse.

Step 4. Set your cold brew ratio: concentrate vs ready-to-drink

Your ratio decides flavor, flexibility, and fridge space. Most folks brew a concentrate, then dilute each glass to taste. Prefer zero math at pour time? Brew ready-to-drink by adding more water upfront. Here’s how to make cold brew either way, with proven ratios from home-kitchen winners.

• Concentrate (classic, flexible): 1 cup coarse grounds : 4 cups water (about 1:4 by volume, ~1:8 by weight). Fairly concentrated—great over ice or with milk.

• Concentrate (extra-strong): 1½ cups grounds : 3 cups water (1:2 by volume). A bold base you’ll cut more aggressively.

• Ready-to-drink (skip later dilution): Brew with the water you usually add in the cup. Quick math: if you typically cut concentrate 1:1 (equal parts), use roughly double the water during brewing; if you cut 1:2, use triple. Example: for 1 cup grounds, instead of 4 cups (concentrate), brew with 8 cups for a strong ready-to-sip batch.

• Tip: Ratios are a starting point. If it tastes too stout, add water; if it’s thin, increase coffee next batch. Use filtered water for cleaner flavor.

Step 5. Measure and combine: saturate grounds and stir thoroughly

Time to bring the ratio to life. Measure your coffee and filtered water, add the grounds to your jar or French press, then pour in cool water. Stir thoroughly so every speck gets wet—dry pockets lead to weak, uneven extraction and extra grit later. Use a long spoon to sweep the bottom and sides and keep stirring until the floating raft looks fully moistened. Once everything’s evenly saturated, you’re ready to cover and let it steep.

• Order matters: Grounds in first, then water; stir 15–30 seconds until no dry clumps remain.
• French press note: Don’t plunge—use the lid with the plunger pulled up.
• Seal it: Cover to keep out dust; you’ll steep on the counter or in the fridge next.

Step 6. Steep time and temperature: 12–24 hours, fridge vs counter

This is the set‑and‑forget stage of how to make cold brew. After you’ve stirred everything evenly, cover the vessel and let it steep 12–24 hours. Longer steep = stronger extraction, but not better forever—going past about 24 hours can start pulling harsher notes. You can steep on the counter or in the fridge; both work, and the general timing stays the same.

• Counter steep (room temp): Park it out of direct sun for 12–20 hours. Great when you want maximum extraction without tying up fridge space.
• Fridge steep (cold): Just as easy and already chilled when you strain. Plan for roughly the same 12–20 hours.
• Taste checkpoints: Sample at 12, 16, and 20 hours. Stop when it’s smooth and strong enough for how you’ll dilute.
• Grind matters: Using finer or pre‑ground coffee? Aim for the shorter end to avoid bitterness.
• Optional agitation: A quick stir once midway can help if grounds form a dry cap; not necessary if you saturated well.

Step 7. Strain cleanly: filters, cheesecloth, and avoiding grit

Straining is where your slurry becomes a silky concentrate. Aim for a two‑stage cleanup: first remove the bulk of the grounds, then “polish” the brew so it pours clear and tastes smooth. Take it slow—rushing or stirring the settled grounds kicks up silt and leaves grit in the cup.

• Coarse catch: Pour through a fine‑mesh strainer lined with cheesecloth or a flour‑sack cloth. Paper coffee filters also work; they just drain more slowly.
• French press route: Press the plunger down only partway to separate grounds, then decant. For extra clarity, pour that coffee through a paper or cloth filter.
• Double‑filter if needed: If you see haze or fine silt, run the concentrate through a fresh paper filter once more.
• Leave the sludge: Stop pouring before the thick bottom layer reaches your filter—don’t try to force it through.
• Store clean: Transfer the strained concentrate to a clean, covered bottle or jar and refrigerate.

Step 8. Dilute to taste: how to cut your concentrate (1:1 to 1:3)

You’ve got silky concentrate—now tune it to your taste. Think of dilution as your volume knob: more water or milk lowers intensity, less keeps it bold. Ice will melt and soften the cup, so it’s smart to start a touch stronger and adjust. There’s no single “right” mix when learning how to make cold brew you love—use these baselines, sip, and tweak.

• Balanced everyday: 1:1 (equal parts). Example: 4 oz concentrate + 4 oz water over ice.
• Milk-forward and mellow: Start 1:1 with milk (dairy or plant). Too rich? Add a splash of water.
• Long and light: 1:2 to 1:3 (concentrate:water). Example 1:3: 3 oz concentrate + 9 oz water for a 12‑oz glass.
• Brewed extra-strong (e.g., 1½ cups coffee:3 cups water)? Begin at 1:2 to 1:3 and fine-tune.
• Grab‑and‑go tip: Pre‑dilute a bottle at your favorite cut so it’s ready when you are. Coffee ice cubes keep flavor strong as it chills.

Step 9. Serve it your way: over ice, with milk, or hot cold brew

You’ve nailed the concentrate—now make it yours. Think about temperature, texture, and sweetness. Ice will dilute a little, milk softens edges, and gentle heat turns cold brew into a mellow hot cup. Sweeten smart with simple syrup or flavored syrup, which dissolve better in cold drinks than granulated sugar.

• Over ice: Start 1:1 (concentrate:water). Use coffee ice cubes to keep flavor bold.
• With milk: Try 1:1 with dairy or plant milk; add a splash of water if needed.
• Hot cold brew: Add a bit of water, then warm gently (microwave or stovetop)—don’t boil.
• Bubbly “coffee soda”: Mix 2–3 parts seltzer to 1 part cold brew; sweeten to taste.
• Dessert move: Pour a shot over vanilla ice cream for a speedy faux affogato.

Step 10. Flavor upgrades: vanilla, cinnamon, orange peel, mint

Infusing flavors is an easy upgrade when you’re learning how to make cold brew that tastes “crafted.” Add whole, strainable ingredients directly to the steep for a clean cup, or finish in the glass with syrups/extracts. Avoid powders that cloud and add grit. Start small—cold extraction is gentle but persistent over 12–24 hours.

• Vanilla: Split 1/2 bean into the steep; or add about 1/4 tsp extract per cup after straining.
• Cinnamon: Use 1 stick in the jar; skip ground. Cinnamon syrup keeps texture ultra‑smooth.
• Orange peel: Add 2 wide strips (no pith) for a bright lift—great with chocolatey coffees.
• Mint: Lightly bruise ~6 leaves; add late in the steep or finish with mint simple syrup.

Step 11. Water and ice matter: filtered water and coffee ice cubes

Great beans and ratios can’t outrun funky water. When you’re learning how to make cold brew that’s clean and sweet, start with filtered water. It removes off flavors so the cup tastes rounder and smoother, and it helps your concentrate keep its clarity in the fridge. Ice matters too—melting cubes become part of the drink, so make them count.

• Use filtered water: For brewing and rinsing equipment, it yields a cleaner, sweeter cup.
• Match your ice to your brew: Freeze cubes from the same filtered water so melt doesn’t add odd flavors.
• Make coffee ice cubes: Freeze a tray of cold brew and use those cubes to chill without dilution.
• Pre‑portion cubes: Pop 2–3 coffee cubes into to‑go cups for stronger flavor as they melt.

Step 12. Scale your batch: small, standard, and party-size formulas

Once you’ve nailed your ratio, scaling how to make cold brew is simple multiplication. Pick concentrate strength, then size up or down to fit your week (or your crowd). Use filtered water and keep the same steep and strain steps—flavor stays consistent as you scale.

• Small (1–2 glasses, 1:4 concentrate): 1/4 cup coffee + 1 cup water

• Small (extra‑strong, 1:2): 1/2 cup coffee + 1 cup water

• Standard (fridge batch, 1:4): 1 cup coffee + 4 cups water (yields ~3 cups concentrate)

• Standard (extra‑strong, 1:2): 1½ cups coffee + 3 cups water

• Party size (1:4): 2 cups coffee + 8 cups water

• Party size (1:2): 3 cups coffee + 6 cups water

• Quick math: 1:4 concentrate → water = 4 × coffee | 1:2 concentrate → water = 2 × coffee

• Ready‑to‑drink shortcut: If you normally cut concentrate 1:1, brew with double the water up front (e.g., 1 cup coffee + 8 cups water). Adjust next batch to taste.

Step 13. Storage and shelf life: how long cold brew keeps

Once strained, cold brew belongs in the fridge. Transfer the concentrate to a clean, covered glass bottle or jar and refrigerate. It tastes brightest in the first 3–5 days and generally keeps up to a week; after that, flavor fades and stale notes creep in. Whether you steeped on the counter or in the fridge, always chill the finished brew for storage when learning how to make cold brew you can enjoy all week.

• Store as concentrate: Dilute in the glass for better flavor over time.
• Keep it clean: Don’t store with grounds; leave the sludge behind when decanting.
• Shake before pouring: Fine particles can settle.
• Use good lids: Tight seals prevent fridge odors from hitching a ride.
• Past its prime? If it smells off or tastes flat/woody, brew a fresh batch.
• Pro move: Make coffee ice cubes to chill without watering down future pours.

Step 14. Troubleshooting and pro tips: weak, bitter, muddy, sour

Even simple cold brew can go sideways if extraction is off or straining gets sloppy. The good news: small tweaks fix most issues fast. Start by confirming you used filtered water, a coarse grind, and a sane steep window (12–24 hours). Then use the quick diagnoses below to lock in your perfect, repeatable how to make cold brew routine.

• Weak/thin: Increase coffee or steep longer. Move from 1:4 to a touch stronger, or extend from 12 → 16–20 hours. Lightly finer grind (still coarse) can help.
• Too bitter/harsh: Shorten steep (aim closer to 12–16 hours). Grind coarser. Dilute more in the glass (1:2 or 1:3). Avoid going past ~24 hours.
• Muddy/gritty: Grind coarser. Don’t pour the sludge; leave the last cloudy 1/2 inch. Double‑filter through paper or a cloth after a mesh catch.
• Sour/under‑extracted: Steep longer and/or use slightly finer (still coarse) grind. Verify full saturation—stir 15–30 seconds at the start.
• Inconsistent batch to batch: Measure coffee and water the same way each time, keep the vessel covered, and taste at checkpoints (12/16/20 hours) to stop when it’s right.

Step 15. FAQs: caffeine, pre-ground coffee, espresso roast, decaf

Quick answers to the most common questions that pop up when you’re learning how to make cold brew. Use these as starting points, then adjust to your taste and routine.

• Does cold brew have more caffeine? Per ounce of concentrate, yes. Once you dilute (e.g., 1:1 or 1:2), the caffeine in your glass is similar to brewed coffee and depends on your ratio and serving size.
• Can I use pre‑ground coffee? Yes. Expect faster extraction and a bit more silt. Steep on the shorter side (around 12–16 hours) and double‑filter. Fresh, coarsely ground coffee tastes brighter.
• What about “espresso roast” or espresso beans? Go for it. There’s no required roast—use what you like. Grind coarse and brew to taste; many enjoy darker roasts for a bold, smooth concentrate.
• Can I make decaf cold brew? Absolutely. Follow the same ratios and steps; just choose decaf beans. You’ll get the same smooth, low‑acid profile without the jitters.

Step 16. Sustainable sips: smart ways to reuse spent grounds

When you’re learning how to make cold brew, don’t toss the grounds—put them to work. They still carry aroma and trace compounds that shine in the garden and DIY care. Choose one of these simple, low‑effort reuses and keep your ritual a little greener.

• Boost your beds: Sprinkle used grounds over mulch; when the sun warms them, the coffee aroma is lovely.
• Pest deterrent: Scatter around plants that slugs and snails like; they tend to avoid coffee grounds.
• Mind moisture and acidity: Grounds retain water—don’t overwater, and use around acid‑tolerant plants (e.g., hydrangeas).
• Deter burrowers: Lightly sprinkle in areas with mole/vole activity.
• Body scrub: Mix grounds with coconut or almond oil for a quick exfoliating scrub.
• Second‑pass brew: Steep used grounds again for a lighter, low‑octane cold brew.

Step 17. Fat Frank Coffee bean picks for standout cold brew

Frank’s standards are high and your cold brew should be too. Because we roast to order, you get peak aroma and a cleaner, sweeter cup. Choose beans that match how you drink it: single origins for black, blends or flavored coffees for milk and sweet sips. Grind coarse and start with a 1:4 brew ratio unless noted.

• Cold Brew Coffee (blend): Our fridge-friendly go-to for a smooth, balanced concentrate. Brew 1:4; dilute 1:1.
• Ethiopia Natural (single origin): Lively and fruit-forward, great over ice without milk. Brew 1:4; dilute 1:2.
• Papua New Guinea (single origin): Comforting, chocolate-leaning profile that’s a crowd-pleaser. Brew 1:4; enjoy ready-to-drink.
• African Espresso (blend): Bold and structured—stands up to milk and cream. Brew stronger at 1:2; dilute 1:2–1:3.
• Flavored (Cinnabun or Pecan Pie): Dessert-like cold brew with zero fuss. Brew 1:4; top with milk or oat milk.

Bonus: every order sends $1 to Pawsitively Cats—coffee that treats you and helps cats. Frank approves.

Your cold brew, your way

You’ve got the playbook: what cold brew is, the gear that fits your kitchen, the grind, the ratios, the steep, the strain, and the perfect cut in the glass. Start simple and repeatable: brew a 1:4 concentrate with a coarse grind, steep about 16–20 hours, double‑strain, then pour 1:1 over ice. Taste, tweak, and lock in your house recipe. From there, it’s all preference—fruit‑forward singles for sipping black, bold blends for creamy lattes, flavor infusions when you want a twist.

Ready to put it in the fridge for the week? Grab freshly roasted beans (roasted to order) from Fat Frank Coffee and brew with confidence—every order also sends $1 to Pawsitively Cats. Stock up, set your timer, and let Frank’s favorite ritual become yours. Smooth mornings await.