I tried making meringues for the first time yesterday, using splenda instead of sugar. I didn't have any cream of tartar either. I definitely overbeat them, to the clumpy and a bit runny phase. I baked them anyway and they still tasted fine, they were just extremely crispy throughout.
Today I got some cream of tartar and tried again.
- 2 whites
- bit less than 1/4 tsp cream of tartar
- 1/2 cup splenda
- 1/2 tsp vanilla
They seemed to be going very well through soft peaks, when I added the splenda in a few batches. Shortly after, the vanilla. Maybe it was the extract, but at that point it returned to a runny goop phase, still foamy but no peaks. Two more minutes of beating and it seemed good again, uniformly small bubbles and medium peaks. I stopped here so I wouldn't repeat my previous mistake.
I then put the meringue in a large ziploc bag to use for piping. As I began, I immediately noticed that it was again looking like the previous attempt. The bubbles were getting bigger and less uniform, and the inside of the bag showed collapsed runny whites all over. It was more foamy than creamy.
Where did I screw up this time around? Was the runnyness halfway through a warning sign? I imagine the extract could have added too much liquid.
Edit: The results
Today I got the chance to try again, and it was a success! (I think, they're in the oven…) I added a 1/4 tsp white vinegar as well, and replaced almost half the splenda with granulated sugar. I was worried because I didn't bother processing the sugar finer, but it seemed to do fine.
I added the sugar at around medium peaks, and it did collapse a little back to that runny stage, but not nearly as bad as the previous attempt. Another few minutes and I got them back, and then added the splenda and vanilla.
I made quenelles instead of piping, and it worked well. There was no weeping at all, not a single drop, and the foam stayed smooth throughout.
Best Answer
First of all, I suggest reading through our other questions on meringues and general egg-beating, to rule out any issues with your technique regardless of sugar content:
There are more, but I'm going to stop here - there's already so much about the subject on this site that I'm not going to waste any more time going into details about that. Suffice it to say, make sure you're using the right eggs, the right equipment, and the right ingredients, and doing things in the right order.
More specific to this question, however, is the fact that the sugar in a meringue is not just to make it sweeter. Sugar is a stabilizer; it is a critical ingredient in a meringue, and regardless of what Splenda and its recipes may say, it's not a perfect substitute for sugar.
Most Splenda recipes I've seen still use some sugar (preferably superfine), just less of it. Every little bit helps and you don't need that much. If you're not going to use any sugar then you'd better use some other stabilizer like corn starch, otherwise it's simply not going to be stable (unless, maybe, you've done everything else absolutely perfectly).
By your description, it also sounds possible that you might be rushing through it; "soft peaks" should be fairly smooth, not foamy or bubbly, like so:
If you don't beat long enough to get soft peaks, or if you start adding the "sugar" too quickly, it will collapse. I prefer to err on the side of firm peaks, it doesn't change the end result too much and there's less risk of a collapse. On the other hand, if you massively overdo it (i.e. try to get it all the way to stiff peaks) without any stabilizer, then it almost certainly will collapse, and once it does, you cannot recover it, it's like trying to blow up a balloon that has already burst.
So, to summarize: Try to use some sugar, or at least some starch as a stabilizer once the peaks firm up. Make sure your peaks are somewhere between soft and firm before adding your sweetener/stabilizers - not earlier, not later; and add them slowly enough to properly incorporate - you don't want to see any crystals or bubbles at that point.
(From what I can tell, your meringues failed long before the piping stage, and it definitely wasn't the vanilla's fault.)