The uniqueness of Tokaji Asz (botrytis) wines is not only due to their terroir and the indigenous Hungarian grapes used in the blend (primarily Furmint but also Hrslevel, Muscat Blanc, Zta and Kvrszl), but also the ancient method still generally used to make the wine. Grapes without any botrytis are harvested and made into a base wine. The Asz (late harvest grapes) are picked separately and are then added to this base wine (either whole or made into a paste) in various proportions (puttonyos). The berries, being completely dry and shrivelled, have little or no juice, so this technique allows the berries to swell and therefore enables effective pressing. After fermenting at snails pace (for as long as it takes) the wines are matured for at least two years in Sauternes barrels from Chteau Suduiraut.

The proportion of Asz grapes was historically measured in puttonyos. A puttony is a basket for carrying grapes, so a five puttonyos wine, for example, meant that a wine had five hods of Asz paste added to the base wine. Today the wines are classified by their residual sugar rather than the number of baskets added. The puttonyos can still be listed on the label but only 5 Puttonyos (120 g/L min) and 6 Puttonyos (min 150 g/L) can be labelled as Asz wines.