A friend of ours used to own a chocolate factory, and she would get blanched hazelnuts in big boxes. These were only lightly toasted, if at all, but they were perfectly cleaned – not a single recalcitrant paper skin in the bunch.
I've used both the roast & rub method and the baking-soda method (boil water with a couple tablespoons of baking soda, dump in the nuts and boil for a minute or so, rinse & rub) for blanching hazelnuts. While the latter is vastly preferable, it's hard to get the timing & baking soda quantity exactly right, so either you end up with perfectly clean nuts that are a little cooked (not to mention dyed) looking, or you get nuts that are only mostly clean. So whatever the big suppliers do, it doesn't seem to be either of these methods.
Does anybody have actual experience with blanching hazelnuts on a large scale? What method do they use to get those perfect results?
(Failing that, I'll accept pointers on the baking soda method, i.e. how do I tread that line between dye-bath and ineffective?)
Best Answer
I can't say which things are actually used, but this would seem to confirm my above guess, along with the other one - you can use more chemicals in industry than you would in a home.
Product and process of blanching nuts
Method and apparatus for blanching nuts
Not really helpful for doing it at home. Hard to say which ones are commonly used in industry, of course. You can find a lot more patents along these lines.