Zierfandler
...that the skin of the Austrian white wine grape Zierfandler turns red just before it is ready to harvest?
...that the skin of the <a href="./Austrian_wine" id="mwBO0" rel="mw:WikiLink" title="Austrian wine">Austrian</a> white <a href="./Wine" id="mwBO4" rel="mw:WikiLink" title="Wine">wine</a> <a href="./Grape" id="mwBO8" rel="mw:WikiLink" title="Grape">grape</a> <b id="mwBPA"><a href="./Zierfandler" id="mwBPE" rel="mw:WikiLink" title="Zierfandler">Zierfandler</a></b> turns red just before it is ready to <a href="./Harvest_(wine)" id="mwBPI" rel="mw:WikiLink" title="Harvest (wine)">harvest</a>?