Puresteel / Drip coffee maker, 12 cupAustin, Texas

Clean. Convenient. Plastic Free.

Built from steel and glass. No plastic in the water path.

01Why

Every “stainless steel” coffee maker I found still had hidden plastic valves, tubes, and reservoirs. So I built one without them.

JC Foster, Founder @jcfosterx

02Materials

Built from steel and glass.

No plastic in the water path.

Everything the water touches is stainless steel or glass. There is no silicone in the water path.

03Results

Averages from Puresteel testing, compared with the Specialty Coffee Association ideal ranges.

Puresteel coffee maker / Test resultsPuresteel testing

Average brewing temperatureR1: 200°FAverage across Puresteel test brews.
Total dissolved solids (strength)R2: 1.31%Specialty Coffee Association ideal: 1.15–1.35%.Within range
Extraction yieldR3: 20.3%Specialty Coffee Association ideal: 18–22%.Within range

Fig. 3Strength vs. extraction. Specialty Coffee Association ideal shown in blue.

Notes

1Values are averages from Puresteel testing.
2Ideal box from the Specialty Coffee Association brewing chart: strength 1.15–1.35% total dissolved solids, extraction 18–22%.

04Use

Recommended

2 level tablespoons of ground coffee per 5-ounce cup, about 24 level tablespoons for a full 12-cup carafe. Adjust to taste.

One switch

The switch is electromechanical. There is no app and no firmware.

Cleaning

The 304 stainless steel filter and the glass carafe come out and are dishwasher safe. Descale the tank every 4 to 8 weeks in hard water.

05Mission

Building contaminant-free appliances that help humans thrive.

The coffee maker is our first product. Anything we make after it follows the same rule: no plastic where it touches water or food.

JC Foster, Founder
Austin, TX
@jcfosterx / About