I imagine that it is the other part of the percentage that can make a differernce. What is it and how much?

I believe that I read on David Lebovitz’s blog once that IIRC over 75% cacao will often yield grainy results.

Edited to remove an erroneous statement about fat content.

Kate, I don't understand your question. I gave the only percentages there are.

I tried searching for info and found this: https://www.lakechamplainchocolates.com/what-is-cacao/ From that, I’d say there are two possibilities… either the person who wrote the recipe only tested with certain percentages and is being careful, or it’s because the higher percentages of cacao mean it’s less sweet, and therefore may not produce a result that’s sweet enough.

I'm fine with less sweet. I guess I'm going to use what's left of the 70% bar--more than half of what the recipe calls for-- and add some 85% and hope for the best

I invite Kate’s correction, if I’ve misunderstood, but what I understood her question to be is if 85% is cacao, what makes up the other 15%? According to David Lebovitz, the percentage that is not chocolate liquor, which is what 100% ground cacao beans is called, can be made up of many things which may affect how the chocolate tastes and how it behaves when cooked.

The other 15% is sugar and vanilla.

Even when a percentage is listed, it doesn't tell you how much of that percentage is cocoa solids and how much is fat. That differs maker by maker. I think PM is onto something with the author being specific about what was used to make the recipe.

I've read that when you make ganache, it's most likely to break if the fat content is too high. There's also all the things that go on in chocolate. The fat and the crystallization and all that require tempering if melted then solidified. That shouldn't affect a pudding, but I'm still in the camp of chocolate is a great mystery and one must follow instructions--no amount of reading and doing has helped me glean more expertise than that!

Though I can tell you, Lake Champlain Chocolates (where PM linked) are awesome!

If chocolate in recipes was that tricky, wouldn't they have to specify brands instead of just cacao percentages?

Well, yes and no. If they were really up on their chocolate, and if it really made that much difference, then maybe yes. A lot of really good recipes are just kind of wished into existence by a good cook who tried something and it worked. I mean, who thought whisking oil into eggs would create such a versitile emulsion as mayonnaise? Why whisk to start with? It probable just was someone mixing the two, who got rambunctious making it smooth and had a Eureka moment. Eggs are trickier than chocolate, but most cooks know a lot more about them, and they're basic ingredients, without the shroud of mystery of manufactured products like chocolate.

For many purposes, the exact composition of the cacao percentage chocolate doesn't really matter. It's one of those things where you develop a preference for a brand after trying a few things. For less analytical cooks, it's just ”I like it better with this one,” never realizing it was because there was a little more or less fat percentage.

For the pudding, I might be a bit concerned about breaking with the 85%, but IIRC, it has cornstarch, right? That's a good stabilzer, and if it can keep gravy together, why not pudding? I take it the 70% one ounce isn't enough? Because I can't imagine the 2% difference in cacao would make a difference to the pudding. If so, you could give it a whirl with your 85%, being careful of the temperature, and all, or you could save that for something else and wait to get the one you know works.

I had 1.4 oz of the 70% and added the 85% to make 2 oz. It was the best I could manage. It seems to have turned out OK though I haven't yet tasted it.

Those "4 oz" bars are now as small as 3.1 oz. Same size though.

Oh, I hate that! I'm willing to pay the price increase to get the same thing I'm accustomed to! They probably made it just a bit thinner.

Great choice. Use what you have. :)