Comandante C40 MK3 for Percolator

The pot that made American coffee for a century, and the only brewer here that runs the same water through the same grounds over and over. Boiling water climbs a stem, sprays out under the glass knob, falls through a basket of coarse coffee and lands back in the pot to do it again. It works, and it will happily keep going until it has ruined itself.

Comandante C40 MK3

1Zpresso J-Max 102–136

1Zpresso JE 114–138

1Zpresso JX 27–33

1Zpresso JX-Pro 168–200

1Zpresso K-Max 90–100

1Zpresso K-Plus 90–100

1Zpresso K-Pro 90–100

1Zpresso K-Ultra 59–77

1Zpresso Q2 (Heptagonal burrs) 78–114

1Zpresso Q2 (Pentagonal burrs) 78–114

1Zpresso Q2 S 78–114

1Zpresso X-Pro 41–55

Baratza Encore 28–29

Baratza Encore ESP 32

Baratza Sette 270 31

Baratza Virtuoso+ 27–29

Comandante C40 MK3 30–40

Comandante C40 MK4 29–35

Comandante C60 Baracuda 36–50

DF64 Gen 2 50–60

Eureka Mignon Specialita 90–100

Eureka Mignon Zero 82–100

Fellow Opus 29–37

Flair Royal 50–60

Hario Mini-Slim Pro 18–20

Hario Skerton Pro 13–19

MHW-3Bomber R3 Pro 90–110

Mazzer Philos 90–100

Moccamaster KM5 6–8

Niche Zero 45–50

Normcore Manual V2 45–60

OXO Brew Conical 30–38

Option-O Lagom P64 66–96

Timemore C3 Max Pro 17–20

Timemore C3 Pro 17–20

Timemore Chestnut C2 27–33

Timemore Chestnut C3 27–32

Timemore Chestnut S3 80–90

Timemore Chestnut S3 ESP 70–85

Timemore Chestnut X 55–60

Turin DF54 60

Varia VS3 56–60 Weber Key 90–100

Wilfa Svart 75–100

Wilfa Uniform+ 35–41

Manual grinder · 39 mm conical burrs

Comandante C40 MK3's setting

Clicks: 30–40
Grind size: 900–1200 µm
Grind descriptor: Coarse

These settings are consensus values computed from 1 independent sources (manufacturer manuals, reference charts and our micron model), monitored daily for changes.

See the Comandante C40 MK3 grind chart

Overview

Ours 1:15·40 g·600 g·96 °C·Coarse · 900–1200 µm·10 min Make it yours

Brew with us

Percolator

Grind Coarse 900–1200 µm

Ratio 1:

Dose g

Water g

Water temp °C

Total time 10 min

0:00 Timer

— Flow

— Weight

—

STEP 1 / 7 0:00 / 0:00

Notes

We turn the heat down the moment it starts, and we take the basket and stem OUT before pouring — left in, they keep dripping into a pot that is already finished. And we treat the end as a decision: this is the one brewer here where waiting longer reliably makes it worse.

Weigh beans

Weigh out the beans — fresh, not pre-ground.

Grind

Grind coarse.

Add water

Water into the pot, below the basket.

Add the grounds

Level the grounds in the basket.

Bring it up

Heat until it starts to perk.

Perk

Five to seven minutes, low flame.

Enjoy

Lift the basket and stem out, then pour.

Behind every step

1Weigh beans
0:05

Weighing instead of scooping is the only way to repeat a brew — beans differ in density and roast, so a scoop of one is not a scoop of another. Fix the dose and every other variable finally means something.
2Grind
0:15

Coarser than you would think, and for a reason unique to this brewer: the water comes back for these grounds again and again. Sea salt is the texture. Anything finer is already over-extracted by the third pass, and anything small enough to slip through the basket's holes spends the rest of the brew circulating in the pot and ends up in your cup.
3Add water
0:15

Below where the basket will sit — if the water reaches the grounds while it is standing there, the coffee starts steeping before anything has been heated, and it is over-extracted before the pump has done a single cycle.
4Add the grounds
0:10

Level and loose. The basket has holes in the bottom and a perforated lid on top, and water is going to pass through both several times — a heaped bed just channels, and a tamped one is not something this gentle pump can push through.
5Bring it up
4:00

Nothing is brewing yet — this is just the pot getting hot enough to start pumping. It is worth watching, because the moment it begins is the moment the clock starts, and a percolator brought up on a hard flame arrives there already too hot: the first cycles come through scalding and the coffee is bitter before the timer has begun. Medium heat, and turn it down the moment it perks.
6Perk
6:00

The same water, through the same grounds, over and over — no other brewer on this site does that, and it is both what a percolator is and the reason it has the reputation it has. Every cycle extracts a little more from a bed that has already given most of it up, so this is a method where the end of the brew is a decision rather than an event. Five to seven minutes on a low flame. Left to run, it will happily boil itself bitter.
7Enjoy
0:10

Coffee keeps changing as it cools: aromatics fade, acidity sharpens and sweetness comes forward. Drink it soon after brewing, and taste it as it drops in temperature — that's how you learn what to adjust next time.

Fix it by taste

Time first, grind second, and the flame is what governs both. Start at 40 g coarse to 600 ml, medium heat until it perks, then low for five to seven minutes. Bitter? Take it off sooner before you touch anything else. Weak? More coffee rather than more time — with this brewer, more time is almost always the wrong direction.

Bitter, harsh, hollow

It perked too long

Fix · Five to seven minutes from the first perk, then off — this is a decision, not an event
Grounds in the cup

Grind too fine for the basket

Fix · Coarser: anything that fits through those holes ends up circulating
Weak and pale

Not enough coffee, or it never really perked

Fix · 40 g to 600 ml, and wait for a steady rhythm before timing
Boils over

Flame too high after it started

Fix · Turn it down the moment it perks; it only needs to tick over
Fine at first, bitter by the last cup

The basket was left in

Fix · Lift the basket and stem out before you pour

What you need

A stovetop percolator: the pot, a stem, a basket and a lid, usually with a glass knob so you can see it working. Stainless lasts, enamel is the camping classic, aluminium is the old one. There are no consumables at all — no filters, ever — which is exactly why it went to sea, up mountains and into every diner in America.

Beans & roast

A medium or medium-dark roast with some body to it. The recirculation is hard on delicate coffee, and it is unkind to acidity in particular, so a bright light-roast single origin comes out sour and thin here. This is the method where an honest, well-made blend beats an expensive lot — the pot is not going to show you the difference.

Variations to try

Campfire

The original setting; keep it at the edge of the coals rather than over them
Egg coffee

Scandinavian-American: an egg stirred into the grounds settles them and softens the brew
Shorter perk

Four minutes and a slightly finer grind, for something closer to a filter cup

Percolator FAQ

Why do percolators have a bad reputation?

Because the same water passes the same grounds repeatedly, and a bed that has been extracted five times has nothing good left to give. Nothing about that is inevitable — it is a question of when you take it off. Five to seven minutes makes a good pot of coffee; fifteen makes the burnt, hollow stuff the reputation is built on.

How do I know when it is done?

You watch the glass knob. When it starts perking — a steady, rhythmic spurt rather than the odd bubble — turn the heat down and start counting. Five minutes for a lighter pot, seven for a strong one. The colour in the knob tells you the rest.

Do I need to take the basket out?

Yes, and it is the step people skip. Left in, it keeps dripping into a pot that has finished brewing, and the last cup out of it tastes noticeably worse than the first. Lift the basket and stem out as soon as it comes off the heat.