About the Coffee Brew Calculator
Great coffee is a recipe, not a guess. This calculator turns your method, cup size, and strength into the four numbers that actually control the cup — coffee dose in grams, water volume, water temperature, and grind size — plus bloom volume, brew time, and a step-by-step pour schedule for pour-over. It covers nine methods (V60, Chemex, French press, AeroPress, espresso, cold brew, batch drip, Moka pot, and Turkish) and scales cleanly from a single mug to a twelve-cup carafe.
It is built for the new pour-over owner who bought a gooseneck kettle and a scale and now needs a starting recipe, the French-press drinker tired of muddy or weak results, the batch-brew household dialing in a morning carafe, cold-brew makers working out concentrate-to-water ratios, and anyone who wants to stop eyeballing scoops and start weighing.
All of the math runs locally in your browser. Your method, ratios, and saved bean profiles never leave your device — the page makes no network call after first load, and bean profiles are stored in your browser only.
Two variables the calculator cannot see still matter: bean freshness (coffee is best 4–21 days off roast; older beans need less bloom, staler beans taste flat) and grinder quality (a burr grinder’s even particle size beats a blade grinder’s dust-and-boulders mix at any ratio). Use the recipe as a calibrated starting point, taste critically, and adjust one variable at a time — grind first, then ratio, then temperature.
Log this brew with tasting notes. Recall it later from your saved history to repeat what worked.
Save your favorite recipe per bag of beans and load it back with one tap.
Aim for a target brew strength (total dissolved solids) and the tool back-solves the ratio and dose.
How did the last cup taste? Get a targeted fix.
How to Use the Coffee Brew Calculator
Pick your brewing method first — it sets the base ratio, grind, and temperature that everything else builds on. Then choose your cup size and how many cups you want; the tool scales the whole recipe so a solo V60 and a full carafe both come out balanced. Nudge the strength slider toward mild or strong to shift the ratio, and set your roast level so the water temperature matches how the beans extract. Weigh the coffee dose on a scale — volume scoops vary too much — and follow the pour schedule or brew time shown.
The Golden Cup Standard
The Specialty Coffee Association’s Golden Cup defines the target extraction that most people find balanced: roughly 18 to 22 percent of the coffee’s mass dissolved into the water, with a resulting brew strength of about 1.15 to 1.45 percent total dissolved solids. In practice that lands near a 1:16 to 1:18 coffee-to-water ratio for filter coffee. Under-extract (too little dissolved) and the cup tastes sour and thin; over-extract and it turns bitter and astringent. Every method in this tool starts from a ratio proven to sit inside that window.
Pour-Over: V60 vs Chemex
Both are pour-over methods, but they behave differently. The Hario V60 has a large single hole and spiral ribs that allow a fast flow, rewarding a medium-fine grind and an active, staged pour — it produces a clean, bright, tea-like cup that highlights delicate light roasts. The Chemex uses a thick bonded filter that slows the flow and removes more oils and fines, so it wants a slightly coarser grind and a longer total brew time, yielding an exceptionally clean, crisp cup. For both, the bloom — wetting the grounds with twice their weight in water and waiting 30 to 45 seconds — is what lets trapped carbon dioxide escape so the following pours extract evenly.
Immersion Methods: French Press, AeroPress, Cold Brew
Immersion brewing steeps grounds in water rather than passing water through them. The French press uses a coarse grind and a metal filter, keeping oils and a little fine sediment for a rich, full body — steep four minutes, then press slowly. The AeroPress is a hybrid: a short immersion followed by pressure through a paper filter, forgiving of grind and fast to brew. Cold brew steeps a coarse grind in cold water for 12 to 18 hours at a concentrated 1:8 ratio; the low temperature extracts far fewer acids and bitter compounds, which is why it tastes smooth and sweet even before dilution. Always dilute cold brew concentrate roughly one-to-one with water or milk before drinking.
Grind Size in Practice
Grind is the single most powerful lever you have. As a mental map from fine to coarse: espresso is powdered sugar, Moka pot and AeroPress are fine table salt, pour-over is medium sand, drip is coarse sand, and French press and cold brew are coarse sea salt. If your coffee tastes sour and weak, the grind is likely too coarse — go finer to slow the water and extract more. If it tastes bitter and dry, the grind is too fine — go coarser. Change grind before you change anything else, and always adjust one variable at a time so you can tell what fixed the cup.
Water Temperature and Roast
Hotter water extracts faster. Dense light roasts resist extraction, so they want water near the top of the range, 96°C (205°F), to pull out their bright, complex flavors. Dark roasts are more soluble and prone to bitterness, so dropping to around 90–92°C (195°F) keeps them smooth. Medium roasts sit in between at about 94°C. If you do not have a variable kettle, boil the water and let it rest 30 to 45 seconds off the boil to land near 94°C. Espresso machines hold their own tight temperature band of 92 to 94°C.
Scaling From One Cup to a Carafe
Because everything is expressed as a ratio, scaling is just multiplication — but two things change at large volumes. First, bigger batches retain heat better, so a full carafe extracts slightly faster than a single cup; if a large batch tastes bitter, coarsen the grind a touch. Second, pour-over becomes impractical much above 4 cups because the bed gets too deep to drain evenly, which is where batch drip and French press take over. This tool keeps the ratio honest at every size so your morning solo cup and your weekend guest carafe both taste like the recipe you dialed in.
Looking for more kitchen tools? Try the Recipe Scaler to resize any recipe, the Cooking Unit Converter for grams and ounces, or browse all Cooking & Kitchen tools.
Frequently Asked Questions
What coffee-to-water ratio should I use?
A 1:16 ratio (one gram of coffee to sixteen grams of water) is the Specialty Coffee Association Golden Cup standard and a safe default for pour-over and drip. French press runs denser at 1:15, AeroPress around 1:14, and cold brew concentrate at 1:8. The calculator picks a method-appropriate base and nudges it by your strength setting.
How hot should my water be for coffee?
The SCA recommends 90 to 96 Celsius (195 to 205 Fahrenheit) for most brewing. Light roasts extract better near the top of that range because they are denser; dark roasts can go a few degrees cooler to avoid bitterness. Espresso runs 92 to 94 Celsius. The tool sets the temperature per method and roast.
Why does grind size matter so much?
Grind size controls how fast water extracts flavor. Finer grinds expose more surface area and extract faster, so a grind too fine for the method over-extracts into bitterness, while too coarse under-extracts into sourness. Each brewing method has a sweet-spot range, which the tool describes in plain language and grinder settings.
What does blooming do and do I need it?
Pouring a small amount of water and waiting 30 to 45 seconds lets carbon dioxide degas from fresh coffee. Without a bloom the trapped gas creates channels that cause uneven extraction. The tool builds a bloom step into pour-over recipes; you can skip it for coffee roasted more than three weeks ago, which has already released most of its gas.
Is cold brew stronger than hot coffee?
Cold brew concentrate is two to three times stronger than drip coffee by caffeine per milliliter, which is why it is brewed at a 1:8 ratio and then diluted. After diluting to drinking strength it lands similar to or slightly below hot coffee in caffeine, but tastes smoother because cold water extracts fewer bitter and acidic compounds.
