I take PH and sugar readings before fermentation. My single variety Roxbury Russet was 1.073 and 3.45Ph! The Redfield, Ambrosia and Suncrisp blend and an initial gravity 1.057 and PH 3.61. Split it in half and treated half campden tablets and omitted sulfites from the other batch to see if they are really necessary with quality fresh cider.
I am at the research stage with (Hard) Cider. the goal is to identify the best apples here for High Acidity. Tannins and Aromatics . When you factor in productivity, disease resistance and juice rendered, the list will be short. You want significate sugar content but, that is the very least rare attribute in a cider apple. I then hope to graft over my cider orchard to those varieties so, I can easily produce awesome single variety and blends with no amendments. The problem is that they very attributes needed in great cider have been selectively bred out of most named varieties in the US.
Red Fleshed apples definitely impart the tannic quality and the idea of red hued cider is awesome. Redfield while productive, renderers little juice when pressed and is not the most intensely colored of the refreshed apples. I will continue to experiment with red fleshed apples in cider. So far, the color I have been able to add has not been valuable when scaled up.
Ambrosia is a choice table apple when grown well. Let us know how it does there.