This should help:
http://www.winemakermag.com/new/fresh
I know you are working off of 5 cup increments but were these 5 cups of whole grapes or 5 cups of crushed grapes? You didn't happen to get a weight at any point of the grapes; if not, the next time you pick could you get a weight of even one cup, though five would be better, in the format matching how you actually measures, whole vs crushed?
Do you have a link to the recipe you are using?
Suggestions:
-buy two hydrometers, one is your spare (trust me)
-take the lid off the bucket and clean it & set it to the side, do same with your blowoff tube, now cover the bucket with a clean towel, secure with bungee cord/rope IF you need to but it should just drape over the opening.
-you need to 'punch the cap' down on your batch at least twice a day, three would be even better.
-if you did not do so before you pitched the yeast you really need to add potassium metabisulphite, aka k-meta/KMS/Campden, follow pkg instructions; you need to sanitize this must, stun the wild yeast and allow the wine yeast to dominate
-I would also add pectic enzyme, per pkg directions; grapes are loaded with pectin & failing to address it will leave you with a cloudy wine
-I would also add a bentonite slurry on/around Day 3, start preparation 24 hrs in advance, per 5 gallon batch: heat 1 cup water to boiling, remove from heat, sprinkle 2 tsp bentonite on surface of water, allow to sink into water on its own for 3-4 hours then stir it & then allow to rest at room temp, covered, for a total of 24 hours. It will expand during this time, will be thick clay goop. You then want to stir this into your must in increments, do not just dump it all at once, make sure it is fully incorporated. The action of the ferment keeps it in solution since you add around Day 3. Don't freak over the color change, or be concerned there is now clay in your wine, it all comes out in the wash--well, when you rack it a few times.
-call your area agriculture/county farm extension office, see if they can ID your grapes
Welcome to WMT Christina!!
...Sara