Thank you Gap.

I guess I will try and error with different amounts of vegetable oils...

I saw one of the Ghirardelli recipe for chocolate hazelnuts and according to the their ingredients I saw that they add 6% hazelnuts of the total weight of the product, that means ~3% vegetable oil.

If other forum memebers have empiric knowledge about vegetable fat addition I will love to learn..

Adding fats generally softens the chocolate. You work out the % of fat based on weight.

For instance, if your formula has 10% full fat milk powder (assume 26% fat content), then the milk fat in your formula = 10% x 26% = 2.6% milk fat.

In terms of non-fats and tempering: I don't think non-fat ingredients (eg., skim milk powder) would affect tempering. I imagine it as a solid-type ingredient that just displaces sugar in your formula and gets ground up/refined with all of your other ingredients. This is just a hypothesis from my side, I've no testing or evidence to back it up.

If you want to sell your product and call it chocolate, there may well be limits to what additional fats and non-fats you can use and how much of them you can use.

In terms of other fats, I haven't used them. I would expect them to soften chocolate. I'm not sure how much, say, vegetable fat, you can add to normal chocolate before you turn it into compound chocolate. Most things I've read suggest 4-5% before you start affecting your ability to temper, but this probably differs based on the fat you are using. And as mentioned above, I think some fats can't be added to chocolate if you want to sell it as chocolate.

For some reason I have in my head that, as a rule of thumb, you should try and keep the additional milk fat from milk powder to <15% of total fat (ie., total fat = cocoa butter + additional fat) to minimise any problems with tempering. I'm sure that isn't a hard rule and depends on what type of milk powder you're adding, but it might give you a starting point for testing. So for a 40% fat chocolate, that would give an upper limit of 6% (40% x 15%) milk fat. If your milk powder was 26%, then the milk powder in your recipe would have an upper limit of 6%/26% = 23% milk powder by weight in the total formula.

When I have made milk chocolate, I have added ~5% milkfat but have taken it as high as 6.5% - it depends what you're after from your milk chocolate. 

updated by @gap: 04/29/16 03:46:24

Hi,

A few months ago I went through all the relevant topics in this forum and in Alchemy forum. I don't remember a lot threads regarding this subject.

I found two:

http://chocolatetalk.proboards.com/thread/460/hazelnut-ratio

http://chocolatetalk.proboards.com/thread/106/nuts-chocolate

In essence, vegetable oil (like hazelnuts)  is liquid in room temperature not like butterfat, so whole milk powder is different from nuts oil.

I just want the experience of people because this issue is a bit vague, how do you count the ratio of the additional fat: by weight or just the ratio to cacao butter? what is the limit of vegetable oil that transform the product from chocolate to kind of nut center?

The questions is aiming also to the final product not just the tempering.

If you have addtional knowlenge to contribute I will be more then happy.

Thank's again

I think you'll find those topics have been answered a few times here.  I'd urge you to do some exploring in the forum archives 8-)

I want to ask a tricky question/issue:

If you dig inside the "bean to bar" or artisan small scale business (or even some big manufacture chocolate producers) you find two main different kinds of ways to give a special taste to the chocolate (not infusion):

1. mixing additional fat in chocolate: coconut, sesame, hazelnuts and more (even whole milk powder)

2. additional ingredients that not including fats: non fat powder milk, spices etc

After this small briefing I have two questions:

1. How the non-fat ingredients effect tempering? for example if I put skim milk powder how it will affect?

2. As I know, as a rule of thumb more then 5% additional fat will affect tempering, what is your experience with addinal fat?

I would like to hear your opinion,

Thank's