Laudator Temporis Acti

Alfred Zimmern, The Greek Commonwealth: Politics and Economics in Fifth-Century Athens, 4th ed. (Oxford: Clarendon Press, 1924), p. 47, n. 2:

On the 'scrub' see Myres, Greek Lands and the Greek People, p. 24, who is, however, in error in saying that, owing to the absence of berry-bearing plants, 'the Greek world is, in general, a jamless world.' 'On the contrary,' writes Mr. Atchley, it is par excellence a berry-bearing country. Blackberries are abundant, whilst myrtle, lentisk, arbutus, juniper, bryony, all produce quantities of berries. Wild pears are abundant all over Greece, wild plums are not uncommon, while raspberries and strawberries abound in Pindus.' It was the lack of sugar, not of berries, which made ancient Greece jamless.

But cf. Andrew Dalby, Food in the Ancient World from A to Z (London: Routledge, 2003), p. 275:

Quinces could be boiled with wine and water to make a kind of pulmentarium (Pliny NH 15.58). There are many recipes and instructions for conserving them so as to retain their food value through the winter, whether whole or cooked down. They combined particularly well with honey. Recipes can be found for kydonion syn meliti 'quince in honey' and kydonion en staiti 'quince in fat' (Oribasius CM 41.20 quoting Rufus of Ephesus): see Grant 1999 pp. 111-12 for modern interpretations of these. A more homogenised product, a distant ancestor of modern quince marmalade or quince cheese, was kydonomeli or melomeli, mentioned by Columella (DA 12.47): a recipe for this is supplied by Dioscorides (MM 5.21 = Oribasius CM 5.25.16). A fermented drink, essentially a fruit wine, was made from this and was known in Greek as hydromelon (Dioscorides MM 5.22; Galen BM 6.744). There is also a recipe for steeping quinces in grape wine to make what was known in Greek as kydonites oinos or melites oinos 'quince wine, apple wine' (Dioscorides MM 5.20). Finally there is a recipe for a kind of quince jam, known as cydonites, a preserve with the consistency of honey (Palladius OA 11.20); and one for a quince syrup or cordial, to apo ton kydonion melon (Oribasius CM 5.20 quoting Philagrius). All these conserves had medicinal uses, and it is generally in medical sources that the recipes are found.