3 hours ago, teonzo said:
Your explanation is correct.
You need proper water/fat ratio and proper method to get a fine emulsion. Which does not mean your method is not correct: what matters is the final result, if during the preparation you face separated phases but at the end you get the proper result, then it's not a problem. See the Valrhona technique for ganaches, they willingly separate the emulsion in the middle stages.
You got a separation of phases because when you added the first quantity of butter there was too low water for emulsifying the fat in butter. You are starting with a caramel at 118°C, which means really few water (I don't have the tables here, I'm pretty sure in one of your books there are the tables of the water content in syrups at each °C). Then you add butter. When you mix this butter you are going to reverse its phases: it's going to change from a water-in-fat emulsion (butter) to a fat-in-water emulsion (caramel), so you need enough water to coat the fat droplets. Butter is around 82% fat and 15% water (at least here), the water in a 118°C caramel is really low, so you don't have enough water to produce a proper fat-in-water emulsion at that stage. Beware that the critical stage is the beginning: you need a high enough water-to-fat ratio to create a proper fat-in-water emulsion, then you can add more fat and maintain the emulsion (think about making mayonnaise). If the ratio is not in the correct window then the emulsion separates, you can get it back when you restore the correct ratio, which is what happens when you add the fruit puree. So you don't need to think you are making something wrong, it's just part of the method you are using.
When adding butter to caramel you are always going to reverse the butter phase. Which means that when you are reversing it, the butter emulsion separates, then it re-emulsifies with inverted phases (from water-in-fat to fat-in-water). During this stage the original butter emulsion is separating no matter what, that's the goal of the recipe/method. Most of the times it's happening at microscopic level, droplets separates and re-emulsify quick, so you don't see the separation stage because it's on a small scale (and you don't see if you did it properly, see the case when caramels separate after days). With the method you are using you see a separation at macroscopic scale in the middle stages, which is not a problem. The problem would be if you did not get a proper emulsion at the end of the method, which does not seem to be your case.
Teo
Thanks for the detailed and helpful explanation. Would it make a difference if the butter were added to the caramel while it is still cooking? I know some people do that. It would not look so much like making an emulsion, but ultimately it's the same mixture.
And what about the case of "standup" caramels, intended to be cut and wrapped or dipped in chocolate and therefore cooked to a higher temp? Do those work only if the amount of butter is not so high?
