Ask the Alchemist #85


This is a follow up to Ask the Alchemist 83. Is this why it is so difficult to temper in the summer? I have had very little success as I started with my house around 77°F. I am able to get the slab chocolate down to 82-83°F, but I either don’t get any chocolate to be in temper, or just portions of a few trays.

I think you are asking if you are not forming Type V crystals when you can only get to 82 F. And is this why you can’t get a good temper?

The answer to this is no. That is not the issue. I’ve been doing a lot of tempering tests (I’ve not forgotten all of you who responded about helping me test, I’m almost done designing what I want you to test). And one thing I found out during many of the tests was just how critical the ambient temperature is while the chocolate is setting up.

It’s actually a pretty complicated reason, but I found it interesting…but NOT when I was trying to confirm a result from a previous test. The short answer is that you can’t let your chocolate take too long to set up or it won’t. It will bloom. You can do everything absolutely perfect, have lots of Type V seed, bring it right to 88 F and if you let it set up at 77 F, you have a good chance of failure, but if you are at 65 F, it turns out perfect.

From a bit a research, what I think is happening is that as the Type V crystal structure starts to form, heat is given off. Crystallization in this case is a exothermic reaction. If you can follow, it is why when you add salt to ice (like to make ice cream) it gets colder. That is the opposite, so it is endothermic. You are destroying the salt crystals and that takes energy, so it cools off. If the ambient temperature is too warm then the heat that is given off has no reason to go anywhere, so it stays in the chocolate….and heats it up…and destroys your crystals. Eventually, the V is all gone, or at least disrupted, so Type IV starts to form again, and your chocolate blooms. When the ambient is cooler, heat is carried away, and your Type V crystals can condense (form) into their proper structure.

The solution? Refrigeration. It is really the only way to go in the summer. But…(you knew that was coming), it is possible to cool too fast. If you cool too fast, then the Type V don’t have time to propagate fast enough, any old crystal will form, and again you have bloom. I wish I had an exact method I could give you, but I don’t (yet). But suffice to say that in regards to ambient temperatures, if your chocolate is not starting to harden in 10-15 minutes, you are in trouble. It just isn’t cool enough. What you should do then is put your chocolate into the refrigerator (after resting 10 minutes at room temperature) for 10-15 minutes, then pulling them back out (assuming your ambient is below 80 F) and letting them set. If it’s above 80, either leave them in the refrigerator or just wait for another day when it is cooler. This is why most professional chocolate makers and chocolatiers have cooling boxes where it is 50-60 F. It’s the baby bear zone, as it were. Not too hot, not too cold, but just right.

Although this may not help you temper on hot days, hopefully it will at least help you determine whether or not you should try.

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