How Much Charcoal Does a Josper Use? UK Weekly Cost

By Klim Artemov, founder of Globaltic

Short answer: Josper's own figures put daily charcoal use at 6–8kg for the HJX-20, 10–12kg for the HJX-25 and 16–20kg for the HJX-50. Over a six-day week, an HJX-25 burns 60–72kg, which is four to five 15kg bags of holm oak lumpwood. At our public retail price that's about £136–£163 a week, or roughly 28–34p per diner at the oven's recommended capacity. Trade prices bring that down.

Large pieces of Globaltic Spanish holm oak lumpwood charcoal

What Josper says each oven uses

These are the manufacturer's figures. "Diners" is Josper's recommended capacity for each model.

Model	Recommended for	Daily charcoal	Fire-up time	One load lasts
HJX-20	about 40 diners	6–8kg	about 25 min	7 hours
HJX-25	about 80 diners	10–12kg	about 30 min	9 hours
HJX-50	about 175 diners	16–20kg	about 40 min	9 hours

Josper ovens work at 250–350°C inside a closed box. That's why they use far less fuel per diner than an open grill: the heat stays in.

Turning that into bags and pounds

Assumptions: six trading days a week, 15kg bags, and our public retail price for Spanish Holm Oak 15kg (£33.90 inc VAT, October 2026). Trade prices are lower and ex VAT, so treat these as a ceiling.

Model	Charcoal per week	15kg bags per week	Weekly cost at retail	Per diner at capacity
HJX-20	36–48kg	2.4–3.2	£81–£108	34–45p
HJX-25	60–72kg	4.0–4.8	£136–£163	28–34p
HJX-50	96–120kg	6.4–8.0	£217–£271	21–26p

How the per-diner figure works: daily kilos ÷ recommended diners × price per kilo. For the HJX-25 that's 10–12kg ÷ 80 diners × £2.26/kg ≈ 28–34p.

Two points stand out:

Bigger ovens are cheaper per diner. An HJX-50 uses about 1.7 times the charcoal of an HJX-25 but is rated for more than twice the diners.
A quiet night costs nearly as much as a full one. The oven still needs a full load to come up to temperature. Per-diner cost rises sharply when covers fall.

For trade prices by delivery zone, use our charcoal per cover calculator.

Five things that push consumption up

Damp charcoal. Damp fuel lights slower and burns cooler, so you burn more to get the same heat. Store bags off the floor and under cover.
Lots of small pieces. Fines and small chunks pack tightly, choke the airflow and burn out fast. A closed oven works best on a bed of large, dense pieces.
Leaving the door open. Every opening lets heat out and pulls air in, which makes the fire burn harder.
Lighting too early. If the oven is ready an hour before the first ticket, that hour is paid for in fuel. Time the fire-up to service.
Vents left wide open. Open for fire-up, then close down to hold temperature. A fire running at full draught all night burns through the load.

Which charcoal suits a Josper

Josper's manual says to use only charcoal as fuel, with no lighter fluids. Beyond that, what matters is size, density and dryness.

Spanish holm oak is the lumpwood we recommend for Jospers. It comes in extra-large pieces, 40–200mm and up, from dense holm oak. It holds 4–6 hours of steady heat on a single load in a closed Josper and needs roughly one refuel in an 8-hour asado service. The flavour is sweet and rounded, with an Iberian character.

Globaltic charcoal bags on a pallet in the warehouse

Frequently asked questions

How much charcoal does a Josper use per day?

By Josper's figures: 6–8kg for the HJX-20, 10–12kg for the HJX-25 and 16–20kg for the HJX-50.

How much does it cost to run a Josper a week?

An HJX-25 on six days a week uses 60–72kg of charcoal. At our public retail price for holm oak lumpwood (£33.90 per 15kg), that's about £136–£163 a week. Trade prices are lower.

How long does a Josper take to heat up?

Josper quotes about 25 minutes for the HJX-20, 30 minutes for the HJX-25 and 40 minutes for the HJX-50.

What is the best charcoal for a Josper?

Large, dense, dry lumpwood. Spanish holm oak is a common choice. It gives 4–6 hours of steady heat on a single load in a closed Josper.

Why is my Josper using more charcoal than expected?

The usual causes are damp fuel, too many small pieces, the door opening often, lighting too early, and vents left open after fire-up.

Get a quote for your Josper

Tell us your model, your covers and your trading days through our hospitality page, and we'll work out your weekly bags and quote your zone price. A trade account opens from a two-bag order, so you can test holm oak in your own oven first.