I'm getting ready to start my 3rd kit it is Wineexpert private reserve Zinfandel. My first two, although drinkable tasted like they oxidized a little. Like red wine left out overnight. The first I never topped off the final carboy and had about 3 inches of head space below the neck . The 2nd batch I topped off but after it sat about a week with similar headspace. I don't want to make the same mistake. Do I need to top off in the clearing step or after clearing into final carboy? Any help would be appreciated.