Whisk at high speed until the mixture is cool, about 3 minutes. About 1 minute before the end, you can add food colouring, if not done at the almond paste stage. The mixture should increase in volume and become firm and shiny, and it should be thick and marshmallowy and you have a beak when you lift the whisk.
- clump in picture
https://pizzarossa.me/2015/10/27/a-step-by-step-guide-to-macarons-using-the-italian-meringue-method/
Once the syrup reaches 248F, remove from heat and white the mixer running at the highest speed slowly pour the syrup between the bowl and the whisk.
Continue whipping for about 8-10 minutes and until the bowl is cool to the touch.
The meringue will be stiff, but a whisk dipped into meringue and lifted will have a peak that slightly bends.
https://letthebakingbeginblog.com/2018/03/basic-macarons-italian-meringue-method/
At the same time, put the water and sugar on the stove over medium-high heat and attach your candy thermometer. When the mixture gets bubbly all around with no spots of unboiled water (or 240 degrees F) pour the sugar syrup into the egg whites and turn up the speed of your mixer to high. Let it beat until the bowl of the mixer is warm to the touch (body temperature).
http://loveandmacarons.blogspot.gr/2013/01/macaron-recipe-italian-meringue-method.html
It seems like you are pouring the syrup in the centre of the bowl. This will cause it to splatter on the side of the bowl and not incorporate into the meringue. To prevent this, pour the syrup slowly down the side of the bowl.
Also, make sure you mix at a medium-low speed when adding in the syrup, then increase to medium. Mixing it too fast can deflate the meringue.
Lastly, be sure that you don't stop mixing until the meringue has cooled down. Touch the side of the bowls, and when it is cool to the touch, it should be good.
https://www.reddit.com/r/Baking/comments/3ip7lg/macaron_meringue_italian_method_is_liquidy_and/
Well I have some a minor breakthrough in that I've found I can get pretty darn close by turning the hand beater up to MAX pretty much immediately after adding the sugar syrup. Also beating the eggs until they are firm/almost separating also helped. I noticed that my mix cooled down a lot faster than some videos noted, and I think part of the issue is the fan for the hand mixer blasts into the bowl (design flaw??) thus cooling it down quickly. I was able to skip the reheating step doing this! yay. But now I have hollow shells :'(. The challenge continues XD. thanks for the advice all!
https://www.chowhound.com/post/trouble-whipping-italian-meringue-1060133?page=2
Remember to turn down the mixer speed before adding the hot sugar syrup to avoid getting splashed! Pour the syrup in a slow stream down the side of the mixer bowl into the egg whites, then turn the speed back up to high and let it run until a beautiful billowy white meringue forms and it has cooled slightly.
A little “beak” formed of meringue. If you get this your meringue is in good shape. It should be stiff and shiny.
https://dessertfirstgirl.com/2010/10/making-macarons.html
You have to beat the meringue for quite a long time — 15 or 20 minutes — and measure the temperature along the way.
"I think the common mistake most people make is not to make the Italian meringue correctly," Tian said.
When the sugar syrup reaches 244 degrees, slowly pour the syrup in a steady stream along the sides of the mixer bowl while the mixer is whisking. Continue to beat until stiff, glossy peaks form and the meringue has cooled to about 95 degrees, about 15 minutes.
http://www.montereyherald.com/article/zz/20120501/NEWS/120508418
Egg Whites
Egg whites are usually aged out on the bench for 2 to 3 days. Place them in a glass container covered with plastic wrap and cut a small slit in the top of the wrap. This helps them to dehydrate. Alternatively, they can be microwaved for 10 - 20 seconds on medium high, which will give the same results. Egg whites must be at room temperature as they whip and hold better at room temperature. Dried egg white can also be added (2% of the egg white volume) to tighten and stabilize the meringue to give it slightly more holding time but this is optional. This is added at the soft peak stage. Three large egg whites will weigh approximately 100 grams.
Whipping egg white increases the volume and incorporates air. Because of its low surface tension and the stability of the surface, the egg white forms a foam. Start beating slowly, gradually increasing speed.
The stiffness of the meringue can be determined by it’s appearance, the height of peaks and the extent to which the point bends over when the egg beater is lifted out of the meringue, and also how it flows when the bowl is partially inverted.
Soft peak: When slightly whipped, air bubbles are large and the egg white appears foamy, transparent, and very runny. With more beating the bubbles become smaller, the egg white less transparent, whiter and still flows if the bowl is partially inverted.
Slip and streak stage: The egg white has soft peaks and it will hold the shape of a bird’s beak.
Stiff peak: The egg white becomes stiffer as it is beaten and as the air bubbles divide and become smaller. The amount of egg white utilized in forming films is greater. The small air bubbles with fine cell walls are stronger and more rigid than a few large cells. The eggwhite becomes very white, begins to lose a little of the moist, shiny appearance, and is stiff and rigid. When the bowl is inverted, the egg white does not flow and remains in the bowl and the end of peaks stand up straight.
Dry: If the egg is left to stand, the watery fluid collects at the bottom of the bowl more slowly. With longer beating the eggwhite becomes dry, loses its shine and becomes curdled and patchy.
Italian Method
The Italian meringue method is better for large batches. The egg whites are whisked until the volume is approximately 8 to 10 times the original. It is then combined with a hot sugar syrup. The meringue is more stable and gives more consistent results than the French or Spanish methods. There is more scope for playing with the batter. You can divide the batter and add different colours and flavours. The batter is softer and shinier and you don't have to dry the piped macarons as long. It may seem a little difficult at first, as the meringue and the sugar syrup must be ready at the same time, but it really is very easy once you have tried it and well worth the effort. Italian macarons are baked at approximately 150˚C.
The meringue
The egg whites are whisked until they appear foamy, then cream of tartar is added. Then it is whisked further until they reach the slip and streak stage and the volume is approximately 8 to ten 10 the original. It is important not to overbeat at this stage. Use a medium to medium-high speed to get a stable foam with uniformed sized air bubbles (speed 6 on Kitchen Aide). A small pinch of dried egg white can be added at this stage to tighten and stabilize the meringue.
Adding the Hot Syrup
When the sugar syrup reaches 118˚C, it is removed from the stove and immediately poured down the side of the mixing bowl into the whipping egg whites. Recipes I have read vary from 118 to 121˚C, so don’t worry to much if it goes over a little.
The volume of the whipped egg whites visibly increases. Colour is now also mixed in. Mixing is continued at medium speed until the mixing bowl is cool to the touch and the meringue has thickened and reached a workable temperature of around 35˚C.
http://bakeitoff.blogspot.gr/2009/10/macarons-tips-tricks-and-how-to.html