I'd love to eat sunchokes (aka Jerusalem artichokes or topinambour) more frequently, but the side effects (gas, abdominal discomfort) are a bummer. In a home kitchen, how can I prepare the sunchokes to prevent this side effect?
In On Food and Cooking (2004 edition), page 307, Harold McGee indicates that the... erm... flatulent effects of sun chokes (also called Jerusalem artichokes) are due to complex fructose-based carbohydrates that are not digestible by humans.
Long, slow cooking allows enzymes present in the fresh of the tuber will convert these fructose over time. McGee recommends 12-24 hours at 200 F / 93 C.
He indicates that the result will be soft and sweet, akin to a vegetable aspic.
Note that the ogliosacharrides in beans are a different class than the inulin in sunchoke (galactose based versus fructose based, respectively), and evidently Beano is not effective sunchoke.
Short of this extreme measure, your best defense against wind may be smaller portions of the vegetable.
Harold McGee addresses this subject in his excellent book, The Curious Cook (1990). He explains the Jerusalem artichoke in great detail in the chapter titled, "Taking the Wind out of the Sunroot." His conclusions are (a) the quantities of the responsible carbohydrate are somewhat dissipated during cold storage of a month or more, (b)"about half of the remaining indigestibles can be removed by boiling in a large volume of water for 15 minutes, and finally (c) "A larger proportion can be broken down into fructose by cooking for 24 hours." This final conclusion has made me consider using a water bath (sous vide), but I have not gotten around to the experiment.
By the way, for those of you considering a planting...once you plant them, you are stuck with them. The multiply like crazy and are difficult to eradicate. Your best bet is a contained raised bed.
Our Topinambour grows in the flower bed, not in the vegetable garden, so no need to dig all of them up. We harvest as much as we need for one meal during winter and leave the rest in place. Last harvest is in late winter/early spring, just before the tubers start sprouting again. Looks pretty in summer when flowering, too.
As we haven't noticed any nasty side effects (yet?), I'm led to believe that harvesting them during winter when dormant is equivalent to 6 weeks of cold storage.
I asked a similar question to this (missed it while searching because I was not aware of the nameSunchokes) and the answers I received have been merged into this one. I was asked to provide the information from my original question as an answer here. Since some of the answers might look out of place in reference to the original quetion I will try to provide the context they were given in.
The gaseous effects of Sunchokes are caused by the high content of a carbohydrate called Inulin. Our digestive system is not able to digest this carb, while the bacteria in our colons absolutly thrive on it.
As one of the other answers outlines: the most accepted remedy is cold storage or late harvesting. When left in the groud during the winter, the tubers transform the inulin, thus enabling us to effectively digest the Sunchokes. This means that if you are growing your own, you can just harvest the tubers on the day you eat them, provided you do so late in the season.
If you grow your own and find that you need to harvest them all at once it is best to leave the soil on them, wrap them in a cloth and leave them in a cool and dark environment for 4 to 6 weeks. If you buy them from a store and you are unsure about how long they were stored before going on sale, that makes it quite hard to be sure and I also do not know if the tubers will keep for weeks once cleaned.
Regardless of the storage method, there will always be a amount of Inulin left in the tubers, which brings us to the question from the OP: how to cook them to minimise the effect.
I have played around with cooking methods a bit. My conclusions:
- A long cook, while getting rid of much of the Inulin does not do it for me. Sunchokes are best when they retain a crunchiness and I find their texture dissapointing when overcooked, kind of like when you cook sweet potatoes for a minute too much. Obviously this effect is negated when used in a blended soup, which is why we use them for this dish quite a lot.
- Stir frying at really high temperature does have a positive effect. While I am not certain about which chemical transformation takes place, the caramelisation due to the high heat levels seems to change the chmical composition of the product sufficiently to take care of most of the problem.
Some recipes suggest adding caraway and/or asafoetida (hing), and these spices are there for a reason - they are known for reducing gas.
The idea has been presented that if you lactoferment sunchokes, the fermentation process converts most of the inulin into simpler carbohydrates that don't cause the gas. The idea is to let the microbes have their way with the sunchokes -before- they enter your digestive system.
There's tons of info on youtube and the web about lectofermenting veggies, which provides other health benefits (besides preventing super gas) like improving the the gut bacteria, which aids your immune system.