I have made an OG 1.060 apple cider (Gravenstein apples and added sugar), fermented with Red Star Pasteur Champagne yeast. It has fermented out to SG 1.002, has been stored for about 5 months, and has very little body and surprisingly little flavor compared to my earlier attempts, using Wyeast 4766.
Is there a way to increase the body post-fermentation?
If you carbonate it, that carbonation should give it a perceived fuller body. Aside from that, you could try adding some grape tannin or some acid blend, as those should help it feel fuller and more complex.
Here's a pretty decent primer from the Norther Brewer on basic cider making that covers these points in brief:
https://cdn.shopify.com/s/files/1/2785/6868/files/cider.pdf
On tannin addition:
OPTIONAL: Add tannin. Tannin helps the cider's "grip" and structure. These are sensations more than flavors, but can add wonderful complexity to the finished product. Start small, as it doesn't take much to get the desired effect. Liquid or dry tannin can be used to equal effectiveness. Remember, it's always possible to add a little more, so err on the side of caution.
On acid additions:
- OPTIONAL: Add acid. Most juice, especially juice made from later season apples, will have a lot of sweetness, but little acid. Acid helps to balance the cider by adding sharp, crisp character. Small amounts of malic acid can be added to taste, up to one tablespoon in five gallons. To ensure more accuracy and repeatability, consider measuring the pH or using an acid titration kit to determine approximate acid content. Remember, it's always possible to add a little more, so err on the side of caution.
There is a lot of other good general information in that pdf. If you plan on making more ciders, I think it's worth it to give it a quick read.
Additional tannins and acid can lead to better mouth feel.
The best hard cider and wine apples are those that are both high in tannin and malic acid. I look for cider that, please excuse the expression, makes your balls ache when you drink it. That’s what I use to make my apple wine.
If you don't mind a bit of a cheat: some maltodextrin can work miracles in apple cider for improved body and a little bit of balanced sweetness.
