Description from Sweet Maria's Coffee
This is the king of vacuum coffee brewers. We are one of a handful of coffee sources that offers Cona Vacuum Brewers. These are beautiful, elegant, and a bit scientific-looking; aficionados of these believe it’s the ultimate brewing method. I think the results are remarkable …I have never brewed a bad cup on the Cona. They are used in a handful of fine inns, B&B’s and restaurants.
Its main feature is that the coffee is entirely prepared in glass; there’s no contact with metal or plastic components. Because it operates by a vacuum principle, coffee is always infused at the precisely correct temperature every time, and over-extraction is not possible. It’s the brewing method for romantics, and is prepared at the table with heat provided by the spirit lamp.
We currently stock the largest Cona Size D (1 quart/1.13 liters capacity) in polished chromed cast steel or gold tone, and the C model (1.5 pints capacity). We strongly recommend the D model: 2 pints is not that much coffee by American standards. The C size would be fine for preparing coffee for 1 person, or two if you prefer small cups of coffee.
Something to consider: because of the design of the vacuum brewers, there is always a small amount of water that does not ascend to the top. This means that brewing less than the full capacity of the brewer makes more diluted coffee. Match the brewer capacity to the amount of coffee you think suits your needs! Besides, adding too much water adds to the risk of an overflow. We have also been told that brewing at a higher altitude can add to the risk of an overflow as well
Denatured alcohol must be used in the spirit lamp, and it is widely available at hardware stores (in the solvents section) and camping/boating stores. The lamp does not ship with alcohol. Unforatunately the butane burner we carry cannot be used with this model.