A Neat Little Paper

[reelchemist]

As my forum name suggests I am a chemist, synthetic organic by training and moving into the area of wine chemistry in my current position. Anyway I have been getting to know the wine chem literature and I thought I'd scope the choc chem literature and found a nice little paper on the roasting of Malaysian Cocoa Beans

Ref: Influence of roasting conditions on volatle flavour or roasted malaysian cocoa beans, Nazaruddin Ramli is the corresponding author, published in the Journal of Food Processing and Preservation, vol. 30 pg 280-298, 2006.

Just google the title and you'll find the abstract which summarises the major findings, obviously I can't post the article or I'll be in trouble. Anyone with access to a University library shouldn't have any trouble.

I shall distill the article down for those that can't and it is quite amazing reading Howards thread on his various roastings that you don't need a GC-MS to roast chocolate - who would have thunk it? The findings on bitterness, sourness, cocoa flavour, burnt flavour and astringency and their developement through the roasting process exactly map Howards. Although the paper does back it up with chemical profiles - Oooooo.

Anyway the optimum temp and time for roasting Malaysian cocoa beans (they don't specify variety in the paper) is 30 min at 150C. The also found cocoa flavour increases with an increase in time and also temperature of roast (to a point - burnt flavour also follows this pattern), astringency decreases as temp increases and length of roast increases, bitter taste decreases as a function of roast temperature to 150C and then increases again at 160C (the tests were done on 10C increments). Finally sour taste was a bit mixed up but a general decrease in sour taste as increased roast time was observed.

So, what Howard said, infact I find Howards method and descriptions more practical. Personally I won't be roasting my first lot or any after in the lab and preiodically checking the chemical profile on my GC as the roast proceeds. I think judging by the scientific approach that I have seen in most of what I have read on the forum, this was just and excersise in stating the bleeding obvious.

[sugaralchemy]

The paper sounds interesting. I may have to dig up a copy. I have looked at a few others in this same category - processing of cacao, from fermentation to roasting. The downside to this is that there's such a great degree of variability involved, it's hard to precisely quantify scientifically. Because of this, chocolate is a mixture of art and science, unless you have a nearly unlimited budget to extensively isolate and control all variables.

You have varying base raw cacao, varying fermentation (it's not exactly a scientifically controlled incubation process!), and while roasting may be more precisely controlled, the variability in the base material being roasted is going to be considerable, resulting in constantly, subtly differing results.

[reelchemist]

I agree it would vary sooo much. Just on the topic of scientific papers, I found a bunch at www.worldcocoafoundation.org in the 'cocoa information centre' under 'research documents'. Some are quite interesting, I am not sure if they are general access or that I have access due to loging in from the work computer which has access to these journals online anyway.

[sugaralchemy]

reelchemist - did you get my private message?

[reelchemist]

Hey, thanks for putting that post up about getting your PM, I use other forums but this one is layed out a little differently and I didn't see the top corner until now.