When to blend?

When in the wine making process is the best time to blend? Is there an advantage to do so before stabilization? During bulk aging? I have two WE batches underway, one in secondary, one finishing primary, I can blend now or wait. What are your experiences and is there any science on the best moment to blend? If it matters, the two varietals are Montepulciano and Sangiovese.

Those are really good on their own, especially the Montepulciano. What has prompted your decision to blend?

I agree they are good on their own......I have made them both but here is my take on the verietals on there own. Sangiovese is the range of wines I enjoy the most, from Chianti, to Brunello and Vino Noble. Yet it tends to be acidic, structured, austere and tending towards red fruit. Great food wine, hard to enjoy as a sipper. I also like Montepulciano but it's a little flabby, unstructured, low acidity and is more blue fruit. Really nice young and doesn't need food to be enjoyed. So I thought they would compliment each other and make a more complex blend. I really don't know but have had some commercial wines with these two grapes that seemed interesting. I would hope for the best of both but I worry that it won't work. Would like to blend well and give it the best opportunity for it to be a harmony.

I'd wait until they are both clear and ready. Then do some bench trials, AKA taste tests. Better yet, have a blending party. Could make for a fun night with a few friends to try different blends, along with the wines on their own to see what the consensus is.

I would do exactly as Jim said, Except for the part of the blending party, unless my friends brought their own wine. Most of them already mooch more wine from me than they deserve.