Hi there guys,

Im wondering if anybody has any experience with vanilla interacting adversly with the acids in a batch of chocolate bringing out a strong sour flavor? When adding the same vanilla to a batch made with a less acidic bean it did just fine. Mind you were talking half a teaspoon of seed scrapings to 30lbs of chocolate, not very much, but a very distinct diffrence before and after addition of the vanilla. To the point of, in my opinion, ruining the chocolate.  

We used 1kg of cocoa beans (70% dark chocolate)  with 35 mg of vanilla (not extract) .  We used a very acidic cocoa  bean and a mild acidic cocoa bean.  24 to 72 hours of conching.  The strong flavor (not good) was the same regardless of the conching time.  I guess too much vanilla.  Any suggestions in the percentage of vanilla that should be used? 

I would not expect vanilla to have any ability at all to increase sourness.  Perhaps taste your vanilla directly (or disperse it in water) - to see if there's a defect in your vanilla bean.  Any defect that would result in sourness should be very visually obvious, i'd think,  unless the beans were soaked in vinegar or something. 

If you're using a single fold extract (ie 1x strength), 0.5% is usually sufficient.  Obviously tastes vary, but that's a good starting point to consider.  Add towards the end as vanilla's a fairly volatile flavor and if you add it at the beginning of a 72hr grinding cycle, you're going to lose quite a bit of it.

Thanks Sebastian for your suggestions. We conched again chocolate for 48 hours and then we put vanilla. We tasted the chocolate  a few times during the first 10 minutes and then we stopped the conching process. The vanilla taste started to dissapear after 10 minutes.

Our previous bad experienced with the chocolate flavour might have been caused by a bad batch of cocoa beans, definitely not because of the vanilla.