When insufficiently matured grapes freeze on the vine due to early frost in late summer or autumn, cell walls are ruptured, rendering the berries unsightly brown to purple. The wine gets a rusty, yellow to orange-red color, has a typical grassy and foul odor and tastes grassy-sweetish to disgusting. This wine faults
is in the must with activated carbon
and in the wine by means of blue fining
fought. For fully mature berries frost
(at least minus 7 ° C) for the production of Eiswein
not only desirable but even essential.