# Cona Vacuum Brewer Source: https://dailyextraction.com/methods/cona/ Last updated: 2026-10-20 > A Cona is an all-glass vacuum brewer with a glass rod filter. Fill the lower bowl with hot water, put medium or coarse coffee in the funnel at about 50 g per litre, and light the spirit lamp. When the water boils, seat the funnel; the water rises and brews for 2 to 3 minutes. Snuff the flame and the coffee is drawn back down through the glass filter. ## At a glance - Ratio: 50 g per litre - Grind: Medium (sand) - Category: Vacuum & Siphon (Vacuum) - Difficulty: Intermediate - Origin: United Kingdom, 1910 - Also known as: Cona coffee maker, Cona vacuum coffee maker, Cona Size D, Cona D Genius ## Steps 1. **Fill the lamp**: Fill the spirit lamp with denatured alcohol or bio-ethanol, to no more than 1 cm below the neck, and let the wick soak. 2. **Fill the bowl**: Fill the lower bowl with hot or boiling water to within 1 cm of the base of the neck. Dry the outside and seat it in the stand. 3. **Add the coffee**: Put the funnel in its holder, place the glass rod filter in the centre and add medium or coarse coffee, about 50 g per litre of water. 4. **Heat and seat**: Light the lamp. When the water starts to boil, put the funnel into the bowl with a slight twist. The water rises into the funnel. 5. **Infuse**: Let it infuse for 2 to 3 minutes. 6. **Snuff and draw down**: Put the extinguisher cap on the lamp. As the bowl cools, the coffee is drawn back down through the glass filter. 7. **Serve**: Remove the funnel and pour from the bowl. The **Cona** is a British **all-glass vacuum brewer**. Like a [siphon](https://dailyextraction.com/methods/siphon/), it uses heat to push water up from a lower bowl into a funnel of coffee, then a vacuum to draw the brewed coffee back down. What sets it apart is the **glass rod filter**: a solid glass rod that sits in the funnel's spout, so there's no cloth or paper to replace. Cona traces its first patented design back to **1910**. Here's how to use one, following Cona's own instructions. ## The short version - **An all-glass vacuum brewer**, with a spirit lamp and stand. - **A glass rod filter**: no cloth or paper needed. - **Cona's ratio:** about 50 g of medium or coarse coffee per litre of water. - **Infuse for 2 to 3 minutes**, then snuff the lamp to draw the coffee down. - **Size D holds up to 1.1 litres**, good for 4–8 cups. ## How does a Cona work? The Cona works on the same principle as every vacuum brewer: 1. **Heat** from the spirit lamp builds vapour pressure in the sealed lower bowl, pushing the water up into the funnel. 2. **The coffee infuses** in the funnel for a couple of minutes. 3. **Snuff the flame**, the bowl cools, and the vacuum draws the coffee back down, past the **glass rod filter**, which holds the grounds back. The glass rod rests in the funnel's spout **by its own weight**. Cona dates the introduction of its glass filter to 1947. ## How much coffee should I use? Cona's own instructions say about **50 g of medium or coarse coffee per litre of water**, roughly 1 oz per pint. For a Size D filled to its 1.1 litres, that works out at about 55 g. ![Chart of coffee grind sizes from extra fine to extra coarse, with medium highlighted for the Cona](https://dailyextraction.com/diagrams/grind-size.svg#medium "Cona's instructions call for a medium or coarse grind.") ## How do you use a Cona, step by step? These steps follow **Cona's user instructions**: 1. **Fill the spirit lamp** with denatured alcohol or bio-ethanol, to no more than 1 cm below the neck, and let the wick soak. 2. **Fill the lower bowl** with hot or boiling water, to within 1 cm of the base of the neck. Dry the outside and seat it in the stand. 3. **Put the funnel in its holder**, place the glass filter rod in the centre and add the coffee. 4. **Light the lamp.** When the water starts to boil, put the funnel into the bowl with a slight twist. 5. **Let it infuse** for 2 to 3 minutes. 6. **Put the extinguisher cap on the lamp.** The coffee is drawn back down. 7. **Remove the funnel** and pour. Brew mode on this page times the infusion for you. ## What sizes are there? | | Size C | Size D | | --- | --- | --- | | Capacity | About 1.5 pints (Remodelista) | Up to 1.1 litres (Cona) | | Serves | Fewer cups | 4–8 cups (Cona) | Cona's current range includes the **Size D "Genius"** all-glass model. ## A short history of the Cona - **1910:** Cona says its first patented design, by **Albert Cohn**, was a laboratory-style "extraction column". - **1947:** Cona dates its **glass rod filter** to this year. - **1950s:** the Aberdeen Art Gallery and Museums collection holds a Cona **Model Rex**, an electric version with a heating element in the base, dated 1950–1959. - **1962:** Cona says production of the **modern Cona design** began, and it became a design classic. Its redesign is credited to the graphic designer **Abram Games**; sources disagree on the exact year. ## Cona vs other vacuum brewers | | Cona | [Siphon](https://dailyextraction.com/methods/siphon/) | [Balance siphon](https://dailyextraction.com/methods/belgian-balance-siphon/) | | --- | --- | --- | --- | | Filter | Glass rod | Cloth, paper or glass rod | Cloth | | Layout | Stacked, all glass | Stacked | Side by side | | Flame | Snuffed by hand with a cap | By hand | Automatic | ## How do you clean a Cona? Let everything cool. Empty the grounds from the funnel, rinse the funnel, glass rod and bowl, and dry them. *General guidance only. The Cona uses an open flame and hot glass under pressure: keep it away from anything flammable, never leave it unattended and follow Cona's instructions.* ## Cona vs other methods - **[Siphon](https://dailyextraction.com/methods/siphon/):** the general vacuum pot. - **[Belgian balance siphon](https://dailyextraction.com/methods/belgian-balance-siphon/):** side by side, with an automatic flame cut-off. - **[Chemex](https://dailyextraction.com/methods/chemex/):** another glass classic, as a pour-over. - **[French press](https://dailyextraction.com/methods/french-press/):** full immersion, with a heavier cup. Explore every vacuum brewer in the [vacuum chapter](https://dailyextraction.com/methods/vacuum/). ## Words used in this guide - [Extraction](https://dailyextraction.com/glossary/extraction/): Extraction is the process of water dissolving flavour compounds out of ground coffee. - [Pour-over](https://dailyextraction.com/glossary/pour-over/): Pour-over is a way of making filter coffee by hand: you pour hot water over ground coffee in a filter cone and let it drip through into a cup or jug. - [Immersion vs percolation](https://dailyextraction.com/glossary/immersion-vs-percolation/): Immersion brewing steeps all the coffee in all the water at once, as a French press does. ## FAQs ### How does a Cona coffee maker work? It's an all-glass vacuum brewer. Heat pushes the water from the lower bowl up into the funnel, where it brews with the coffee. When you snuff the flame, the bowl cools and the vacuum draws the coffee back down through a glass rod filter. ### How much coffee do you use in a Cona? Cona's own instructions say about 50 g of medium or coarse coffee per litre of water, roughly 1 oz per pint. ### What is the Cona glass rod filter? A solid glass rod that sits in the funnel's spout by its own weight. The coffee is drawn down around it while the grounds stay above, so there's no paper or cloth to replace. ### How big is the Cona Size D? Cona lists the Size D at up to 1.1 litres, good for 4–8 cups. There's also a smaller C size. ### Who invented the Cona? Cona says its first patented design, by Albert Cohn, dates from 1910, and was a laboratory-style "extraction column". The modern Cona design went into production in 1962. ## Sources - [CONA coffee maker user instructions](https://www.cona.be/ConaUserManualUK2025.pdf) - [CONA coffee history](https://www.cona.be/conahistory.html) - [CONA product description](https://www.cona.be/ConaProductdescriptionUK.html) - ["CONA" Model Rex coffee maker](https://emuseum.aberdeencity.gov.uk/objects/135456/cona-model-rex-coffee-maker) - [Cona vacuum brewer](https://www.remodelista.com/products/cona-vacuum-brewer/)