Yeast should not be adversely effected affected by tannins at the levels in cider, otherwise red winemaker would have a hell of a time! Imho wine tannins are a great way to go. Remember the addition rates in ciders are going to be MUCH LESS than those indicated for wine and the best measure is to add to taste rather than rely on a recipe. If your not having success with wine tannins it may be the quality of tannins used. The results obtained are exceptionally quality specific and unfortunately the homebrew industry has historically been an outlet for sub commercial quality product.
ThatKiwiWineBloke
>25 harvests in 4 continents and counting!
NZ,AU,ESP,FR,RU,US