The Home Barista’s Guide to Espresso Dosing

Getting your espresso dose right matters more than almost anything else you’ll do at the machine. Dose determines extraction quality, flavor balance, and whether that expensive single-origin pulls sweet and complex or sour and thin. Most home baristas chase grind adjustments and fancy gear when their real problem is dosing 16 grams into an 18-gram basket or stuffing 20 grams where 18 belongs. Fix your dose first, and everything else gets easier.

Dosing means the weight of ground coffee in your portafilter basket before extraction—nothing more, nothing less. Modern specialty coffee measures in grams using digital scales because volumetric measurements fail when bean density varies between roasts. That dose creates the foundation for your brew ratio, affects water flow resistance through the puck, and determines whether your shot channels or extracts evenly. The science is straightforward: more coffee means more surface area and deeper puck depth, which increases contact time and changes extraction yield. Too little coffee and water rushes through in 15 seconds leaving you sour and disappointed. Too much and the puck smushes against the shower screen causing channeling and bitterness.

This guide covers everything you need to dose accurately at home—from understanding standard ranges to troubleshooting when things go wrong.

Start with the right amount for your basket

Single shots call for 7-9 grams but rarely appear in modern specialty coffee due to difficult extraction in single basket geometry. The double shot is your standard, and here the numbers have evolved. Traditional Italian espresso used 14-18 grams, but the contemporary specialty coffee world doses 16-20 grams, with many cafes now using 18-22 grams. According to the Barista Guild of America’s survey of 275 professionals, 66% use 18-20 grams as their standard dose with 1:2 ratios producing 36-40 gram yields.

Your basket size determines your dose range. Most home machines use either 54mm portafilters (Breville, Sage) or 58mm portafilters (commercial-style machines like Rocket, ECM, La Marzocco). The 58mm is the industry standard with better accessory compatibility and slightly more even water distribution due to wider, shallower pucks. A 54mm basket creates deeper pucks for the same dose, requiring slightly finer grind adjustments.

Match your dose to your specific basket capacity within 1-2 grams. An 18-gram basket works best with 17-19 grams of coffee. A 20-gram basket wants 19-21 grams. Underdose by more than 2 grams and you’ll get soupy pucks with fast channeling. Overdose and the coffee contacts the shower screen, creating uneven extraction and bitter flavors. Leave at least 5-6mm of headspace between your grounds and the portafilter top.

Precision baskets from VST and IMS offer straight walls and refined hole patterns that improve consistency. These allow ±1-2 gram dose flexibility around their nominal capacity. If you’re serious about espresso quality, upgrading to a precision basket delivers more value than most machine upgrades.

Understanding brew ratios changes everything

Brew ratio describes the relationship between dose and yield—your input coffee weight to output espresso weight. The modern standard is 1:2, meaning 18 grams of coffee produces 36 grams of liquid espresso. This ratio balances sweetness, acidity, and body for most beans and drinkers.

But ratios are tools, not rules. Ristretto shots use 1:1 to 1:1.5 ratios (18 grams in, 18-27 grams out) creating concentrated, syrupy espresso with heavy mouthfeel. These work brilliantly for dark roasts and milk drinks where you want strong coffee presence. Normale shots at 1:1.5 to 1:2.5 ratios deliver balanced extractions versatile for straight espresso or milk drinks. Lungo shots at 1:3 to 1:4 ratios pull longer yields emphasizing clarity and origin characteristics, often better for light roasts requiring higher extraction percentages.

The key principle: changing yield simultaneously affects both strength and extraction. Pull more liquid and you extract more while making the drink weaker. Pull less and you extract less while making it stronger. You cannot separate these variables by adjusting ratio alone. To increase extraction at the same strength, you must grind finer until channeling begins.

Three methods to dose accurately

Weighing by scale gives you the gold standard. Place your portafilter basket on a scale, tare to zero, and grind until you hit your target weight. Accuracy within 0.1 grams is achievable with decent scales costing $25-80. This method accounts for bean density variations between roasts, enables precise recipe replication, and remains essential for dialing in new coffees. The workflow adds 5-10 seconds but eliminates guesswork entirely. Every serious home barista should weigh doses.

Dosing by grinder timer works well after calibration. Set your grinder to dispense for a specific duration, then weigh the result to verify accuracy. Adjust the timer in 0.1-0.2 second increments until hitting your target dose consistently. This method suits integrated setups and busy mornings, providing 85-90% accuracy (within 0.25-0.5 grams when calibrated). The downside: you must recalibrate whenever changing beans, grind settings, or experiencing humidity shifts. Bean density changes from roast level or age also impact accuracy.

Dosing by sight relies on basket fill level. Before distribution, grounds should mound approximately 1.25cm above the basket rim. After distribution and tamping, the coffee bed should sit about 6mm below the rim. This traditional method costs nothing and works with any grinder, but accuracy suffers—typically within 0.5-1 gram variance, heavily dependent on bean density and grind size. Professionals note 25% volume variations even with experience. Use this method as a secondary check when weighing, not as your primary technique.

Dial in by taste, not just time

Lock your dose to your basket capacity first—this variable stays fixed during dialing. If using an 18-gram basket, commit to 18 grams and keep it there. Now adjust grind size to achieve a reasonable extraction time, starting around 25-35 seconds as a baseline. Don’t obsess over exact timing yet. Some light roasts pull beautifully at 40 seconds while some turbo shots work at 15-20 seconds.

Taste tells you what to adjust. A balanced shot shows sweetness, bright acidity without sharpness, complex flavors, and smooth mouthfeel with pleasant aftertaste. Sour shots with thin body and sharp tanginess indicate under-extraction—either from too-coarse grinding or occasionally from underdosing. Bitter shots with dry, astringent mouthfeel signal over-extraction from too-fine grinding or overdosing. The confusing case: tasting both sour and bitter simultaneously means channeling from poor puck preparation, not simple dose or grind issues.

Start with a 1:2 ratio and adjust based on taste. If sour, increase your yield to 1:2.5 or 1:3, extracting more from the coffee. If bitter, decrease yield to 1:1.5, extracting less. Once your ratio delivers good balance, grind as fine as possible while maintaining that balance. Finer grinding increases extraction, body, and complexity up to the point where channeling begins. Back off one step coarser when flavor declines.

Adjust dose when you’re struggling with extraction despite proper grind settings. Light roasts tasting sour even with long ratios and fine grinds often improve by dosing down 1-2 grams to 16-17 grams. This seems counterintuitive but reduces puck density, allowing water to penetrate dense light-roasted beans more evenly. Conversely, adjust grind not dose when shot timing is simply too fast or slow with proper puck condition.

Common mistakes kill your shots

Underdosing shows up as soupy pucks, fast extractions under 20 seconds, thin crema, and weak sour taste. Using 14 grams in an 18-gram basket creates excessive headspace between puck and shower screen, letting water flow around the top rather than through evenly. Fix this by increasing dose to match basket capacity. The puck should be firm and dry when knocked out, not muddy and loose.

Overdosing reveals itself through shower screen impressions on the spent puck, water pooling on top during extraction, uneven spurting flow, and bitter taste despite reasonable timing. Coffee needs expansion room during extraction. Pack 20 grams into an 18-gram basket and the expanding puck smushes against the screen, creating channels and uneven extraction. Reduce dose by 1-2 grams and leave proper headspace.

Uneven distribution causes multiple simultaneous problems—spraying from bottomless portafilters, off-center extraction, and confusing flavor profiles mixing sour and bitter notes. Clumpy grounds from your grinder create density variations in the puck. Water finds paths of least resistance, over-extracting some areas while under-extracting others. The solution is WDT: Weiss Distribution Technique using 0.35-0.4mm needles to break up clumps throughout the puck depth. Insert needles vertically to the basket floor, making overlapping circular motions covering the entire surface. Work from outside to center, then center to outside. This takes 5-10 seconds and dramatically improves consistency.

Adjust your dose for different roasts

Light roasts demand different treatment than dark roasts due to fundamental structural differences. Light-roasted beans stay denser and less porous with lower solubility. Dose light roasts at 16-18 grams even in 18-gram baskets. This counterintuitive approach reduces puck resistance, allowing water to penetrate dense coffee more evenly. Pull longer ratios (1:2.5 to 1:3) at higher temperatures (203-205°F) with extraction times of 28-40+ seconds. Don’t chase the 25-30 second rule with light roasts—some pull best at 45 seconds.

Dark roasts create porous, easily extracted coffee with lower density. These handle 18-22 grams in standard baskets without extraction issues. Pull shorter ratios (1:1.5 to 1:2) at lower temperatures (199-200°F) with faster times around 20-28 seconds. The higher dose and shorter ratio showcase syrupy texture and chocolate notes while preventing over-extraction and bitterness. Dark roasts need less work to extract—respect that by not over-dosing time or temperature.

The science: roasting breaks down cell structure, increasing porosity and solubility as roast level increases. Dark roasts have roughly 30% more soluble material than light roasts. This explains why identical doses and grinds produce vastly different results between roast levels. Always adjust dose based on roast darkness, bean origin, and your specific taste preferences.

Troubleshooting starts with the puck

Inspect your spent puck after every shot during dialing. A shower screen impression signals overdosing—reduce by 1-2 grams. A soupy, muddy puck indicates underdosing—increase dose to match basket capacity. Visible holes, cracks, or uneven wetness point to distribution problems requiring better WDT technique. An even, firm, dry puck suggests proper dosing, shifting troubleshooting to grind size or ratio adjustments.

Use bottomless portafilters to see channeling directly. Multiple thin streams, spurting, or gaps showing metal basket through crema all indicate problems. Even extraction shows a single thick stream from the center blonding evenly. Channeling often comes from dose-basket mismatches or poor distribution, not grind issues.

When light roasts won’t extract properly despite fine grinding and long ratios, try reducing dose rather than grinding finer. When dark roasts taste bitter at normal timing with proper puck condition, reduce dose or shorten ratio. When shot timing varies wildly with consistent dose, suspect grinder or distribution issues. Fix dose first, distribution second, then adjust grind and ratio.

Invest in the right tools

Digital scales range from $20-$300 but you don’t need premium models to start. The SearchPean Tiny 2S ($25-35) or Timemore Black Mirror Mini ($60-80) deliver 0.1-gram precision adequate for home use. Budget $20-40 scales work fine for beginners. Mid-tier options ($40-80) add features like auto-timers and flow rate displays. The Acaia Lunar ($250) represents the professional standard with waterproof construction and Bluetooth connectivity, but most home baristas get 95% of the benefit from $30 scales.

Dosing funnels prevent spillage and enable clean WDT technique. These magnetic rings attach to your portafilter basket rim—make sure to match your basket diameter (51mm, 54mm, or 58mm). Expect to spend $10-25 for quality options. The funnel stays on during grinding and WDT, comes off before tamping.

WDT tools matter more than distribution levelers. Look for 6-9 needles at 0.35-0.4mm diameter in a pentagon pattern with center needle. Needles must reach your basket floor (50mm length standard). The Normcore WDT Tool V2 ($25-35) offers professional build quality, while generic Amazon tools ($15-25) work adequately for beginners. Distribution levelers look attractive but research shows they can decrease extraction yield compared to doing nothing—they level surface coffee without distributing through depth. Skip levelers and prioritize WDT instead.

A complete starter dosing kit costs $50-80: budget scale ($25-35), magnetic funnel ($10-15), and WDT tool ($15-30). This delivers immediately measurable improvement in shot consistency and flavor.

Getting it right means tasting it right

Dosing isn’t about following rules—it’s about understanding how weight, resistance, and extraction interact in your specific setup with your specific beans. The 18-gram dose isn’t sacred. The 1:2 ratio isn’t mandatory. The 25-30 second window isn’t absolute. These numbers provide starting points for exploration based on decades of professional experience.

Your best dose balances three factors: basket capacity (physical constraint), bean characteristics (roast level and density), and desired flavor profile (strength and extraction level). Match dose to basket first, adjust for roast level second, then fine-tune by taste third. Keep dose locked during daily dialing, using grind size as your primary adjustment tool. Change dose only when switching roast levels, addressing puck preparation issues, or after optimizing grind without achieving good extraction.

Weigh every dose. Distribute thoroughly with WDT. Leave proper headspace. Inspect the spent puck. Taste critically and adjust based on what you’re experiencing, not what you think should be happening. Master these fundamentals and you’ll pull consistently excellent espresso at home, regardless of whether you spent $500 or $5,000 on equipment. The coffee in your basket matters infinitely more than the machine under your portafilter.