I received the following email from a ChocolateLife member, who gave me permission to post it here:
I'm starting up a group of farmers in the north of Malawi, right next to Matema/Kyela in Tanzania.
We're getting beans from Tanzania that us giving a off flavour reminiscent of grass or a yeasty taste (not smell). The flavor is particularly pronounced in the cacao powder after roasting at 135° C for 20 minutes in a drum roaster. I'm grinding the beans as for chocolate liqueur, and pressing using a vehicle hydraulic jack and large truck cylinder.
- Is this possible to remedy through roasting and conching?
- Where do I start looking for the problem in the fermentation process?
The group we started only produce about 250kg of beans per week, but we'd like to build up a artisanal chocolate business aimed at tourism, if we can get the quality right.
To the best of my knowledge you may be able to process out the grassy notes in the chocolate by roasting and conching but you'd do that at the risk of processing out flavors and aromas you want to keep.
However - there may be a simple solution and it requires an answer to a simple question: How long is it from the time the beans come off the drying pad before they are roasted?
Believe it or not, "fresh" beans need to be aged before they can be used. There's not a whole lot of formal research on this because it's not an issue for most chocolate makers as it normally takes several months for the beans to reach the factory after leaving the farm. If you are roasting the beans within 8-12 weeks of their being removed from the drying pad there is a likelihood that you'll get the notes you're finding, along with yeasty and/or wet cardboard flavors.
I know that it costs to keep beans in inventory before using them, but I would cast about for beans that have been aged for at least 2-3 months before processing them to see if you have the same issues with aged beans.
I think it's great you're looking into a small-scale business that incorporates tourism and please keep TheChocolateLife community apprised of your progress!
I am looking forward to learning more.