I read a lot about various ways to top off. At first I believed that most of you used a similar wine. The more I read, it appears that many use marbles. Just curious.
I used to top off using a sim. wine but now I prefer to just rack down to the next smaller vessel and put any left over in vessels also to use to add back when needed.
I used to top up with similar wine but being a newbie I would leave too much behind thus needing lots of topping up. So now I use marbles for small top ups and rack down to 5gal carboy (plus 1/2 gallon or so) for larger amounts.
With experience (5 to 10 years), you soon learn that you rarely have to top-off when using carboys. Barrels are a different matter. In the mean time, use red wines to top off reds, and whites to top off whites.
Or you can play a bit with your own blends. Like if you are making a Syrah, you can top it off with up to 20% of a Viognier to make a Côte-Rôtie (one of my favorite blends!).
I used to top off using a sim. wine but now I prefer to just rack down to the next smaller vessel and put any left over in vessels also to use to add back when needed.
I do as Wade mentions as well if I have an available vessel. Other than that, I use not necessarily a similar wine, but will use a white for a white, or a red for a red. Meaning, for example if I made an Amarone, I didn't go get a commercial Amarone to top off with. I would use a cheap Cab or Merlot.
IN MY CASE IF ITS NOT TO FAR FROM THE NECK,I USE NITROGEN,OTHER THAN THAT THE BEST WAY IS TO ADJUST YOUR VOLUME OF WINE TO DIFFERENT VESSELS,THERE FOR NO OTHER ITEM NEED BE ADD TO THE WINE.......................