Egg separators were something I didn't know about until recently. I've always used the shell to separate them, passing the egg between the two shell halves until the white lets go and falls into a bowl. And let me say up front that there's a reason almost everyone does it that way - it works. But, in the interest of not leaving well enough alone, I have found myself testing out several techniques meant to improve on the shell to shell method.
This whole endeavor can be traced back to a months-long obsession I've had with hollandaise. Specifically, the frequency with which I make it so I can have eggs Benedict at home. Which is to say, all the time. Probably way too often to be healthy. That whole thing has been a fun sort of rabbit hole - dialing in the hollandaise, trying different egg poaching techniques, etc.
But now that we're approaching Egg Nog and Tom/Fernet & Jerry season, egg separation is going to get ramped up periodically. So, when I saw a silicone egg separator at a kitchen store the other week I thought, if it worked, it could actually save some time. And what the heck, it's a kitchen gadget - I need those thing to keep the drawers near the sink from opening too smoothly.
The egg separator I bought looked like the bulb portion of a turkey baster. You squeeze the bulb, put the open end on the yolk and as you release pressure on the bulb the yolk gets sucked up. I bought one and it worked great...70% of the time. Sometimes the opening was a little too big for a particular yolk, other times it was difficult to get enough pressure for the yolk to make it into the bulb without breaking. Occasionally a significant portion of the white would hang onto the yolk keeping it from getting sucked into the bulb and increasing the chances that the yolk would break before making it over the right bowl.
Then I found out about the trick, probably common knowledge, where you use a disposable water bottle in much the same way. This had the added benefit of being clear which came in handy if a yolk broke somewhere along the way. You'd know to clean the bottle (or use another one) before turning it upside down over the eggs that hadn't been separated. That actually worked better than the bulb but we don't use a lot of disposable water bottles and the suction was sometimes still an issue.
Eventually, the idea occurred to me to put some plastic tubing on one of those handheld vacuum sealers used to preserve opened bottles of wine. I tried it and it worked great. The suction is an improvement on the other methods allowing for greater control over the whole operation. If a white stays on the yolk you have a little more time to hold it vertically, twist it around, etc, before the yolk begins to slide down. Also, the tubing pops right off, making it pretty easy to clean.
I poured some boiling water in a jar and put the tube in it while I cracked all of the eggs. The tubing is 1" internal diameter (food grade is what you want) and won't fit over the wine pump unless it gets soaked it in hot water first. The seal after it cools though is solid.
The one thing to keep in mind with this whole thing is that if an egg breaks it's not going to get separated. If it breaks over the bowl containing the unseparated eggs it's a huge drag. Unless you're just doing this for hollandaise. And then you're fine - you really only need enough whites for a couple of Ramos' while the meat gets warmed up. If it's for Egg Nog or Tom & Jerry though, or really anything else where the whites will be whipped up separately, getting yolk mixed in is something to be avoided.
If you're worried about it, or doing a ton, you might want to crack each egg over a small dish before adding it to the larger bowl. If the yolk breaks you have a chance to catch it before it gets mixed in with everything else.
If, after you've put this thing together, you find yourself unable to look at it without cracking up then you've probably done it correctly.
One yolk broke as I was putting it into the second bowl. Again, that's not a huge deal, the yolks are going to get beaten anyway. The key is to move quickly and get the tube horizontal if the yolk looks like it's beginning to slip.
I haven't tried various diameters for the tubing - there might be a better one than what I used. Every now and then there's a yolk that is too small to work. When that happens I just reach in and separate it by hand, letting the white fall between my fingers.
All in all it's pretty cheap to put together. It looks ridiculous but it works. Yes, it is a bit absurd and possibly a great waste of time. This was one of those 'I wonder what would happen if...' ideas though and the process involved in untangling it was mostly enjoyable. Even the small disaster that followed an attempt to use the tubing while reversing an aeropress (broken yolks all over the place).
* Update - While putting this post together was fun, the contraption itself is too ridiculous to bother with. I think I used it once maybe twice before returning to the tried and true method of passing the egg between the two halves of the split shell.