Coffee Dosing Guide: How to Dose Espresso Correctly
Dose accuracy, grinder retention, dosing cups versus rings, and how to stop losing coffee between the grinder and the basket.
Dosing is the least interesting part of making espresso and the most common place it quietly goes wrong. Not because people don't know their target — most home baristas can tell you they're aiming for 18 grams — but because the number that goes into the basket and the number on the scale aren't the same thing.
Coffee gets lost in the chute. Static flings it onto the bench. The grinder holds some back from yesterday and hands it to you today. Two grams disappear and you spend a week adjusting the grind to fix a problem that was never about grind size.
This guide covers what to dose, how to measure it accurately, how to work out what your grinder is keeping, and which dosing tool suits how you actually grind.
What this guide covers
- What coffee dosing is
- How much to dose
- Matching dose to basket
- Weighing before vs after grinding
- Grinder retention explained
- Killing static with RDT
- Dosing cup vs ring vs funnel
- Dosing without losing coffee
- Measuring yield
- Dosing troubleshooting
Quick Answer
Weigh your beans before grinding, to 0.1g, using a dose that suits your basket — around 18g for a standard 14–18g double. Grind into a dosing cup so nothing lands on the bench, then transfer in one clean movement. If your dose out is consistently lighter than your dose in, that difference is grinder retention: measure it once, then reduce it with a spray of water on the beans before grinding. Keep the dose fixed while you dial in the grind, and change only one of them at a time.
What Is Coffee Dosing?
Dosing is the amount of ground coffee you put into the basket, measured by weight. That's it — but two distinctions matter.
Dose is not yield. Dose is coffee in; yield is liquid espresso out. The relationship between them is your brew ratio — 18g in to 36g out is 1:2. People often use "dose" loosely for both, which makes recipes confusing to follow.
Dose is weight, not volume. Bean density varies enormously between origins and roast levels, so a scoop that holds 18g of a dark Brazilian might hold 15g of a light Ethiopian. Any measure that isn't a weight will drift as you change coffees.
How Much Coffee Should You Dose for Espresso?
Match the dose to your basket, not to a universal number. Most home double baskets are built for 14–18g, so 18g is a sensible target. A basket rated 20–24g wants a correspondingly larger dose, and a single basket wants 7–9g. Dosing well outside the basket's range causes problems on its own, independent of grind.
The number everyone quotes for a double shot is 18g, and for most setups that's right — because most home double baskets are in the 14–18g range and 18g sits at the top of it. But the basket is what defines the range, and people rarely check theirs.
Why the basket sets the dose
A basket is designed so a correct dose leaves the right amount of space — headspace — between the tamped puck and the shower screen.
- Dose too small for the basket: the puck sits low, leaving a large gap. Water pools above the coffee and the bed can shift before it settles.
- Dose too large: the puck presses against the shower screen. You'll see mesh imprints on the surface when you unlock the portafilter, and flow gets restricted unevenly.
Precision's laser-cut 58mm baskets come in three dose ranges, all supplied in an aluminium storage container:
| Basket | Dose range | Typical dose | Price |
|---|---|---|---|
| Laser Cut Filter Basket 58mm | 7–9 g | Single shots — around 8g | $33.00 |
| Laser Cut Filter Basket 58mm | 14–18 g | Standard doubles — around 18g | $33.00 |
| Laser Cut Filter Basket 58mm | 20–24 g | Larger doubles and triples — around 21g | $33.00 |
The 10-second headspace check. Tamp a dose, lock the portafilter in, then unlock it and look at the puck. A clean, undisturbed surface means you have room. A ring or mesh imprint means the dose is too large for that basket — reduce the dose, or move to a larger basket. Do this once when you change coffee or basket, not every shot.
Should You Weigh Before or After Grinding?
Weigh the beans before grinding, then check the ground weight occasionally to learn what your grinder holds back. Weighing only after grinding means you're constantly adjusting bean weight to hit a ground target — which works, but hides the retention problem instead of letting you fix it.
Both approaches get you to a correct dose in the basket. The difference is what you learn.
- Weigh beans first (recommended). You control the input, which is the number you can repeat. Weigh 18g of beans, grind, and whatever lands in the basket is the honest output of your setup. If it's 17.4g, you've just discovered your grinder retains 0.6g.
- Weigh grounds after. Grind, weigh, add or remove until you hit 18g. You'll get 18g in the basket — but you'll never know how much coffee your grinder is holding, and topping up means adding freshly-ground coffee to a partly-settled bed.
The practical answer for most people is: weigh beans before, and every few weeks weigh the grounds afterwards to check retention hasn't crept up as oils build on the burrs.
Grinder Retention: How to Measure It and Reduce It
Retention is coffee that stays inside the grinder after grinding — in the chute, around the burrs, in the exit path. It matters for two reasons: your dose is lighter than you think, and the coffee you do get includes grounds left over from the last session.
Measuring your retention
Beans weighed in − grounds weighed out = retention
Weigh exactly 18.0g of beans. Grind into a tared dosing cup. Weigh the grounds. If you get 17.3g, your retention is 0.7g. Run it three times and take the average — the first grind after a change of bean will read differently because you're flushing the old coffee out.
Under about 0.5g is unremarkable. Over 1.5g is worth addressing — on an 18g target that's more than 8% of your dose, and it's stale.
Reducing it
- Spray the beans first (RDT). One or two spritzes of water on the whole beans before grinding — a spray bottle set to fine mist, just enough to dampen them. This dissipates the static charge that makes fine coffee cling to the chute and fly onto the bench. It's the cheapest, highest-impact fix in this entire guide and it costs about two dollars.
- Tap or use a bellows. A few firm taps on the grinder body, or a puff of air through the chute, clears what's sitting loose.
- Purge after a grind change. Grind and discard a few grams so you're brewing the new setting rather than whatever was left at the old one.
- Consider grinder geometry. Purpose-built single-dose grinders use a sloped chamber so grounds fall through cleanly instead of collecting. The GS0 V2 lists a 76.5° sloped grinding chamber and near-zero retention for exactly this reason.
A word on RDT. Water and grinders sounds alarming, but the quantity involved is a light mist on the beans, not a soaking — the moisture is carried out with the coffee rather than left in the machine. If you're unsure about your particular grinder, check with the manufacturer first. The coffee grinder buying guide covers retention and chamber design in more detail.
Dosing Cup vs Dosing Ring vs Funnel
These three get confused constantly. They solve the same problem — coffee ending up somewhere other than the basket — from opposite directions.
| Tool | What it does | Best for | Key published specs | Price |
|---|---|---|---|---|
| Dosing Cup 58mm | You grind into the cup, then invert it over the portafilter. The grinder never points at the basket | Single dosing; weighing beans then grinding; also transfers to AeroPress or V60 | Stainless steel; outer lip sits flush to any 58mm portafilter; approx. 50g bean capacity | $27.50 |
| Dosing Ring 58mm | Sits on the basket and catches overflow while you grind straight into the portafilter | Grinding directly into the portafilter | Stainless steel; fits 58mm portafilters; four finishes — black, rose gold, gold, stainless | $27.50 |
| Large Dosing Ring | Fits over the outside of the basket rather than inside it, so nothing escapes at the rim | Larger doses, messy grinders; doubles as a distribution guide | Heavy-duty stainless steel; fits all 58mm baskets; works as a guide for a needle distributor | $33.00 |
"Dosing funnel" is usually just another name for a dosing ring — a collar that widens the top of the basket so grounds land inside rather than bouncing off the rim. Don't buy both under the assumption they're different tools.
Which one do you need?
- You weigh beans and grind a single dose → dosing cup. Grinding into a cup you've tared is the cleanest path, and it lets you weigh the grounds to check retention.
- You grind straight into the portafilter → dosing ring. It catches what would otherwise fountain over the rim.
- You use larger doses, or your grinder throws coffee around → large dosing ring. Sitting over the outside rather than inside gives more margin, and it earns its keep again as a distribution guide.
- You're not losing coffee and your dose is consistent → you don't need any of them. Don't buy a tool for a problem you don't have.
How to Dose Without Losing Coffee
- Spray the beans. One or two spritzes of water before they go in the grinder. Static is responsible for most of the coffee that ends up on your bench.
- Tare and weigh the beans. Dosing cup on the scale, tared to zero, beans in to your target weight. Use a scale that reads to 0.1g.
- Grind into the cup. Not into the portafilter, not into your hand. Let the grinder finish completely before moving anything.
- Clear the chute. A couple of firm taps on the grinder body, or a puff from a bellows. This is where your missing grams are.
- Invert and lift straight up. Cup over the portafilter, flip in one movement, then lift vertically. Tilting on the way up is how you get the ring of grounds on the bench.
- Check the weight occasionally. Every few weeks, weigh the grounds before you transfer. If retention has grown, it's time to clean the burrs.
Dose Is Only Half the Ratio: Measuring Yield
A dose on its own tells you nothing. 18g in could produce a 25g ristretto or a 60g lungo, and those are completely different drinks. The dose is only meaningful alongside the yield.
The accurate way is to weigh it. Put the cup on the scale under the group head, tare, and stop the shot at your target weight. That's the method to use when dialling in, because grams are grams.
The quick way is a graduated shot glass. The Precision double spout shot glass holds 70ml with graduations in both ounces (0.5oz) and millilitres (10ml), and a double spout for splitting a shot between two cups.
Be clear about what a shot glass measures. Its published accuracy is within ±5%, and it measures volume while your recipe is in weight. Crema volume varies with roast and freshness, so the same 36g of espresso occupies different volumes on different days. That makes a shot glass excellent for serving, splitting and a quick sanity check — and a scale the right tool for dialling in a recipe.
Dosing for Filter and Pour Over
Filter dosing works the same way but with far more tolerance, because there's no pressure and no puck to build resistance.
| Espresso | Filter / pour over | |
|---|---|---|
| Typical dose | 7–9g single, 14–18g double, 20–24g large double | 15g for a single V60, around 30g for a small Chemex |
| Typical ratio | 1:2 (18g → 36g) | 1:15 to 1:17 (15g → 225–255g water) |
| Accuracy needed | 0.1g — small errors move the shot noticeably | 1g is fine — a gram across 250g of water is noise |
| Dose constrained by | Basket range and headspace | Dripper size and server capacity |
| Retention matters | Yes — it's a meaningful share of a small dose | Less — the same 0.7g on a 30g dose is proportionally smaller |
If you brew both, buy to the espresso standard: a 0.1g scale handles filter perfectly well, but a 1g scale can't do espresso properly.
Dosing Troubleshooting
| What you're seeing | Most likely cause | What to do |
|---|---|---|
| Grounds all over the bench after grinding | Static | Spray the beans before grinding (RDT). Fixes most of it immediately |
| Ground weight consistently under bean weight | Grinder retention | Measure it, then tap or use a bellows. If it's over 1.5g, clean the burrs |
| Ring of grounds on the bench after transferring | Tilting the dosing cup while lifting | Invert, then lift straight up vertically |
| Grounds fountain over the portafilter rim while grinding | Grinding into the basket with no collar | Use a dosing ring, or switch to grinding into a cup |
| Dose is right but shots vary anyway | Distribution, not dosing | Dose is only the first step — see the WDT tool guide |
| Screen marks on the puck | Dose too large for the basket | Reduce the dose or move up a basket size |
| Puck sits very low with a big gap | Dose too small for the basket | Increase the dose, or use a smaller basket |
| First shot after changing beans tastes off | Retention — you're brewing a mix of old and new coffee | Purge a few grams after switching, then dose normally |
| Dose drifts when you change coffee | Measuring by volume rather than weight | Weigh every dose. Bean density varies by origin and roast |
Common Coffee Dosing Mistakes
- Not weighing at all. A timed grinder dose drifts as beans age and the hopper empties; a scoop drifts with bean density. Neither is repeatable.
- Changing dose and grind together. Both affect how the shot runs, so changing both means you can't attribute the result to either. Fix the dose, adjust the grind.
- Topping up to hit a number. Adding a sprinkle of coffee onto an already-settled bed creates a loose layer on top that water rushes straight through.
- Ignoring retention. If your grinder keeps a gram, your 18g dose is 17g — and you'll chase that gram with grind adjustments that were never the problem.
- Using a basket that doesn't match the dose. The most invisible of these, because nothing looks wrong until you check the puck for screen marks.
- Assuming dose fixes distribution. A perfectly weighed dose sitting in a clumpy, uneven bed still channels. Dosing and distribution are separate jobs.
Building a Repeatable Dosing Routine
The routine matters more than the equipment. Four habits, and dosing stops being a variable:
- Pick a dose that suits your basket and write it down. Don't change it while you're dialling in the grind.
- Weigh beans before grinding, every time. Same scale, same method, tared the same way.
- Use the same transfer method every shot. Whether that's a cup or a ring, consistency in how you move the coffee matters as much as the weight.
- Check retention monthly. Beans in minus grounds out. If the number is growing, clean the burrs.
Once dosing is fixed, the rest of the espresso workflow — distribution, tamping, extraction — becomes solvable, because you've removed the variable hiding underneath all of them.
Coffee Dosing FAQs
What is coffee dosing?
Coffee dosing is the amount of ground coffee you put into the basket, measured by weight. It's distinct from yield, which is the liquid espresso that comes out — the relationship between the two is your brew ratio. Dosing is measured in grams rather than scoops or volume because bean density varies considerably between origins and roast levels.
How many grams of coffee for a double shot?
Match the dose to your basket rather than a universal figure. Most home double baskets are built for 14–18g, so 18g is a common target. A basket rated 20–24g wants a larger dose, and a single basket wants 7–9g. Dosing well outside the basket's range causes problems independent of your grind — too little leaves excess headspace, too much presses the puck against the shower screen.
Should I weigh coffee before or after grinding?
Weigh the beans before grinding. It gives you a number you control and repeat, and it lets you discover how much your grinder retains — weigh 18g in, weigh what comes out, and the difference is retention. Weighing only after grinding gets you to the right basket weight but hides the retention problem, and topping up means adding fresh grounds onto a partly-settled bed.
What is grinder retention?
Retention is ground coffee that stays inside the grinder after grinding — in the chute, around the burrs and in the exit path. It matters twice: your dose is lighter than you intended, and the coffee you get includes stale grounds from the previous session. Measure it by weighing beans in against grounds out. Under 0.5g is unremarkable; over 1.5g is worth addressing.
Does spraying water on beans before grinding actually work?
Yes — it's known as RDT, and one or two spritzes of fine mist on whole beans before grinding dissipates the static charge that makes fine coffee cling to the chute and scatter across the bench. It's the cheapest meaningful improvement you can make to dosing. The quantity is a light dampening, not a soaking, so the moisture leaves with the coffee. Check with your grinder's manufacturer if you're unsure.
What is the difference between a dosing cup and a dosing ring?
A dosing cup is a separate vessel you grind into and then invert over the portafilter — the grinder never points at the basket. A dosing ring sits on the basket and catches overflow while you grind straight into the portafilter. Choose the cup if you weigh beans and single dose; choose the ring if you grind directly into the portafilter. A "dosing funnel" is generally another name for a dosing ring.
Do I need a dosing cup?
Only if you're losing coffee or want to weigh grounds after grinding. A dosing cup makes single dosing much cleaner, lets you tare and weigh in one vessel, and doubles as a transfer tool for AeroPress or pour over. If you grind straight into the portafilter without spilling and your dose is consistent, you don't need one — don't buy a tool for a problem you don't have.
Can I use a shot glass instead of scales?
For serving and quick checks, yes. For dialling in, no. A graduated shot glass measures volume while your recipe is in weight, and crema volume varies with roast level and bean freshness — so the same 36g of espresso occupies different volumes on different days. Use a scale to dial in a recipe, and a shot glass for splitting shots and a rough sanity check.
How accurate does my coffee scale need to be for dosing?
0.1g for espresso. On an 18g dose, a scale reading only to the nearest gram can be out by enough to shift the shot noticeably — and it can't show you retention differences at all. For filter brewing 1g is fine, since a gram across 250g of water is within normal variation. If you brew both, buy to the espresso standard.
Why does my dose change when I switch coffee beans?
Because you're measuring by volume somewhere in the process — either with a scoop or with a timed grinder dose. Bean density varies considerably with origin, processing and roast level, so the same volume or the same grind duration delivers a different weight. Weighing the beans on a scale removes the problem entirely.
Which Dosing Tool Should You Choose?
Based on the published specifications:
- Single dosing, weighing beans first → Dosing Cup 58mm ($27.50). Stainless, flush to any 58mm portafilter, holds around 50g of beans, and works for AeroPress and V60 too.
- Grinding straight into the portafilter → Dosing Ring 58mm ($27.50). Four finishes, stainless, catches what would otherwise go over the rim.
- Larger doses or a messy grinder → Large Dosing Ring ($33.00). Fits over the outside of the basket, heavy-duty stainless, and doubles as a guide for a needle distributor.
- Measuring the dose itself → a 0.1g coffee scale ($77.00 and up). The one genuinely non-optional item here.
- Splitting and serving shots → double spout shot glass ($22.00). 70ml, graduated in oz and ml, within ±5%.
- Matching the basket to the dose → a laser-cut filter basket ($33.00) in the range your dose actually sits in.
One closing thought. Of everything on this page, two things move the needle far more than the rest: weighing every dose, and a spray bottle. The first costs the price of a scale and removes the biggest variable in espresso. The second costs almost nothing and fixes most of the mess. Everything else is refinement on top of those two.
Precision Coffee Tools is Australian owned and supported, with Australia-wide shipping and a 12-month warranty on coffee machines and grinders. Browse the full dosing tools range, or read the rest of the coffee guides and advice library.