As they have said - I go the freezer route if I don't have enough do a full batch right away. That gives you a couple of advantages. 1) More likely for the fruit cell walls to breakdown after freezing making more juice flavor etc readily avaiable for the wine, or any uses, & 2) Since the fruit is still cool/cold after being thawed out it's less likely to spoil if you let it set overnight for the SG and pH to normalize. I often find that my SG actually goes up after a 12-24 hour wait before starting the ferment. Any longer than that and you risk spoilage, even with K-Meta in the batch.
So I thaw,
Mash/Press the fruit
Add sugar and other needed additives to get my SG and pH balances right (Including a dose of K-meta)
Wait overnight
Recheck the SG and pH and if good,
record those again
Rehydrate my yeast
Pitch yeast
Cover the bucket
And wait.
Since I do my fermenting in a separate building, when I walk into the room the day after pitching the yeast, I can tell right away if the ferment has fired off. The smell is unmistakable. The only thing I need to do is give it a stir, punch down the cap and recover.
PS - The freezer has yielded some interesting findings. It's also in that other building (A second vacant home) and when I go digging to find my fruit for wine making I have found some previously lost bags of fruit. Once it wasn't enough for a batch by itself but when I combined some small bags of Red Raspberry, Blackberry and Black Raspberry, I got just enough for a 1 gallon batch of "Triple Berry" and that turned out the be the most powerfully flavored wine I have made to date. Total pounds was under 6 (something like 5.25 lbs) but those were some great finds that made into a great wine. Sadly there are only 2 bottle left but they are guarded for special use only. Being in the freezer for a couple of years ( ok admittedly 5-6 years in one case) they had lost a lot of the water in them to frost and rendering them more potent once the frost was separated from the fruit itself.