Dialing in Espresso: Variables You Can Control

Dose

What Is It: This is how much coffee grounds you put into the portafilter. This is traditionally weighed in grams. A single espresso shot typically ranges between 7-9 grams traditionally, but modern espresso uses a double dose in drinks and includes a dose of around 16-18 grams. Keep in mind, the dose can go higher, up to 21 or more, depending on the personal preference of the espresso drinker.

When To Adjust: Increasing the dose can allow you to grind coarser, which can help to reduce chances of channeling. Increasing dose can also slow down your extraction time, which can help if your shot is coming out too sour or not enough bitter to balance the shot out. You may need to decrease the dose if you want to be able to grind finer, to improve extraction (explained below). You can also decrease your dose in order to speed up extraction time, which may be helpful if your shot is too bitter or watery. Lastly, you may need to increase or decrease your dose in order to create the correct headspace in the basket. If you have too much coffee in the basket and not enough headspace, the puck may not have enough room to expand and can choke your machine or even damage it by pushing up against the group head (shower screen). If you have too much head space, you will likely see a very soupy puck after your shot, and this also leaves room for your puck to unseat which increases channeling.

Tips: Be aware that if you increase your dose then you have to make sure it is still the right dose for your chosen basket. If you have a basket rated for 18 grams and you go up to 19 grams, you will not have enough headspace and this can cause more issues. Same if you under dose the basket, which is why they make baskets of various sizes.

Ratio

What Is It: This is the amount of coffee grounds you put in the portafilter compared to how much espresso you actually extract. You will typically hear ratios of 1:1, 1:1.5, 1:2, 1:2.5, and 1:3. However this is not a set rule, but a suggestion to start with. So if you use a 1:2 ratio, you would put 16 grams of coffee grounds into the portafilter and extract 32 grams of espresso. Your ratio will of course impact the time it takes your espresso to pull.

When To Adjust: You can adjust your ratio by changing your dose or adjusting how long you run water through the puck. The dose can be adjusted by simply adding more or less to the portafilter, the amount of water pulled through the puck can be adjusted by letting the water run longer or stopping it early. The ratio is often the one of the first variables you should try to adjust when trying to dial in your shot (grind size is the other).

Tips: There are traditional recipes that make great starting points, but they are not set in stone. For lighter roasts start with a higher ratio like 1:3, as the lighter the roast the denser the bean and therefore more difficult to extract. For medium start at 1:2 and for dark roasts start at 1:1.

Grind

What Is It: The grind size refers to how fine or coarse the coffee grounds are. It plays a crucial role in how water flows through the coffee bed and extracts flavors. Grind sizes vary depending on the brewing method—espresso requires a fine grind, while French press uses a coarse grind. The grind affects extraction time, with finer grinds slowing the flow of water and coarser grinds allowing it to pass through more quickly.

When To Adjust: If your coffee is under-extracted (sour, weak, or lacking depth), try grinding finer to slow the extraction and increase contact time. If it’s over-extracted (bitter, dry, or harsh), coarsen the grind to speed up extraction and reduce bitterness. Espresso shots that run too quickly may need a finer grind, while shots that take too long may require a coarser adjustment. For pour-over, a grind that is too fine can lead to clogging and over-extraction, whereas too coarse a grind may result in weak, watery coffee.

Tips: Always adjust grind size incrementally, especially for espresso, as even a small change can significantly impact extraction. Keep in mind that different coffee beans (roast level, origin, processing) may require different grind settings. Also, burr grinders provide more consistent grind sizes than blade grinders, leading to better flavor extraction.

Temperature

What Is It: Brew temperature refers to the temperature of the water used to extract espresso. It typically ranges between 190-205°F (88-96°C). Higher temperatures extract more solubles from the coffee, while lower temperatures extract less. The ideal temperature depends on the coffee’s roast level, density, and origin, as different beans react differently to heat.

When To Adjust: If your espresso is under-extracted (sour, grassy, or lacking sweetness), try increasing the temperature to extract more solubles. If your espresso is over-extracted (bitter, harsh, or drying), lowering the temperature can reduce excessive extraction of bitter compounds. Lighter roasts generally benefit from higher temperatures (200-205°F / 93-96°C) to fully develop their sweetness and complexity, while darker roasts may require lower temperatures (190-195°F / 88-90°C) to avoid extracting too much bitterness.

Tips: Ensure your machine maintains a consistent brew temperature, as fluctuations can lead to inconsistent extractions. If your espresso shots vary in taste from shot to shot, consider using a PID (Proportional-Integral-Derivative) controller to stabilize temperature. Always allow your machine to fully heat up before brewing, and if using a manual machine, consider flushing the group head to stabilize the temperature before pulling a shot.

Time

What Is It: Extraction time refers to how long it takes for water to pass through the coffee puck during an espresso shot. It is measured from the moment the pump is engaged until the last drop falls into the cup. A standard double espresso typically takes 25-30 seconds to extract with a yield of 30-40g. The extraction time affects the balance of acidity, sweetness, and bitterness in the shot.

When To Adjust: If your espresso is under-extracted (sour, weak, or lacks depth), the shot is likely running too fast (below 25 seconds). To fix this, grind finer to slow down the flow, increase the dose slightly, or apply more even tamping. If your espresso is over-extracted (bitter, dry, or astringent), the shot may be running too slow (over 30-35 seconds). In this case, grind coarser to speed up the flow, reduce the dose, or ensure you’re not overdosing the basket.

Tips: Always adjust grind size before dose to fine-tune your extraction time. Keep your technique consistent—distribution, tamping, and puck prep all affect flow rate. If your shot time is inconsistent, check for channeling, which can cause uneven extraction. If you’re experimenting with different coffee beans, be prepared to tweak extraction time accordingly, as lighter roasts often need longer extractions, while darker roasts extract more quickly.

Roast Level

What Is It: Roast level refers to how long and at what temperature coffee beans are roasted, affecting their flavor, solubility, and extraction properties. Roast levels typically range from light, medium, to dark, with lighter roasts retaining more acidity and complexity, while darker roasts develop more caramelization and bitterness. The roast level significantly impacts how the coffee behaves during brewing, especially in espresso.

When To Adjust: If your espresso tastes too sour or underdeveloped, your coffee may be too lightly roasted for your setup. Try increasing your brew temperature (200-205°F / 93-96°C), using a finer grind, or extending the extraction time. If your espresso is too bitter or harsh, the coffee may be too darkly roasted. Lower your temperature (190-195°F / 88-90°C), grind coarser, or shorten the extraction time to avoid over-extraction.

Tips: Lighter roasts are not always the best for espresso, but they can be used. Lighter roasts generally need higher temperatures and longer extractions to fully develop their sweetness, while darker roasts require cooler water and shorter contact time to prevent excessive bitterness. Always adjust your grind size accordingly—lighter roasts are denser and need a finer grind, while darker roasts grind more easily and require a coarser setting. If switching between roast levels, be prepared to tweak multiple factors to maintain a balanced shot.

Puck Preparation

What Is It: Puck prep refers to the process of distributing, leveling, and tamping coffee grounds in the portafilter to ensure even extraction. Proper puck prep prevents channeling (where water flows unevenly through the coffee), leading to a more balanced and flavorful espresso shot.

When To Adjust: If your espresso is inconsistent, uneven, or has fast spurts during extraction, poor puck prep may be the issue. If you notice channeling, weak crema, or a mix of sour and bitter flavors, focus on improving your distribution and tamping technique. Unevenly packed coffee can cause water to flow through certain areas too quickly, leading to under- and over-extraction in the same shot.

Tips: Use a WDT tool (Weiss Distribution Technique) to break up clumps before tamping for a more uniform coffee bed. Always level the grounds before tamping to avoid uneven pressure. When tamping, apply firm, even pressure, but avoid excessive force—it won’t improve extraction. Check for side-channeling by inspecting the puck after brewing; if it looks broken or has dry patches, refine your technique. Consistency in puck prep is key to dialing in great espresso shots.