In this response, which could also be called "What's That Smell?" we have a mystery story.  Duffy Sheardown, the owner and maker of Duffy’s Chocolate (also known as Red Star Chocolate), a small batch bean-to-bar chocolate maker in Lincolnshire, England, was confronted with a very strange circumstance and shares with us how he resolved it.  In addition to being an international award-winning chocolate maker, Duffy is also one of the founders of Direct Cacao, an organization dedicated to improving the lives of the farmers who grow cacao beans by paying good rates for quality beans, ensuring that farmers will be able to continue growing the beans and we can continue to have fine chocolate.  Here’s what he told us:

There are lots of things to say about making chocolate and how exciting it is to find new beans, test new recipes, finally nail a roasting profile. I thought I’d try and share some of the other side of it – when things go wrong and you don’t know why.

In the Spring of 2012 a customer called and said he’d bought a bar of chocolate from me and it tasted horrible. I sent a new bar out and he didn’t get back in touch so I assumed all was well. Then I started getting calls from stockists saying that they’d had complaints and had had to replace bars and refund money. Other stockists were asked to check and the results were mixed – but most of them were happy.

Then it escalated and the happy stockists reported that one bar tasted funny. All of this took about a month and I knew I had a problem. I’d noticed a strong smell outside the factory but it soon dispersed. My wife said she’d noticed it and could smell it on my clothes at home. As far as I could tell the smell had gone but clearly something was wrong.

The Honduras Indio Rojo bar was affected so I sent some beans to a man who judges chocolate awards and they were said to be fine. I’d had tainted beans from that source once before and had put them in a dark corner of the workshop  - maybe the taint had spread from there?

My motor racing background teaches a very important lesson which works perfectly well for many things but not, it turns out, for this situation. If you want to make your racing car go faster – and you do, always – and have bright ideas to try and new parts to try then only try one thing at a time. Otherwise if the car is faster you aren’t sure why and if it is slower you don’t know why either.

I changed the cocoa beans. The new beans tasted OK. Roasted them – they tasted OK. Made the chocolate and moulded it into bars and it all tasted good. The customer sent the bars back. Right, change the sugar and repeat.  Same result. Rats. OK, change the cocoa butter and repeat. Same again. I changed everything and bought new sugar, new beans, new cocoa butter. Changed to sunflower lecithin. Nothing worked. Each of these tests  takes at least a week.

The chocolate being made tasted fine and the samples made when we moulded the bars tasted fine. Then the customers returned the bars and they were horrible again. Argh! Two or three months have gone by now and I have had to tell all my customers that I had a problem and couldn’t supply them.

I spoke to my landlord and said – the unit next door smells funny and I think it’s affecting my chocolate. He moved them out and I checked their unit out. Smelt fine. Same results though.

Eventually I called in a favour from Martin Christie, choc taster and judge. He wouldn’t even go into the moulding area of the factory because of the smell. The conch room was clear, the unit next door was clear – but the moulding room apparently smelt terrible. So, chocolate was OK when I made it and OK when we moulded it – then got tainted as it sat on a tray waiting to be wrapped.

The solution? Open the doors, wide, and blow air through every day for a week. Problem gone away and all I had to do was hire a skip and throw 700kg of fine (!) chocolate away.