Sous vide vs. pressure cooking for vegetables

[Robert Jueneman]

Has anyone done a controlled experiment to compare pressure cooking vs. sous vide for vegetables?

Tonight I cooked two lamp shanks sous vide for 52C for four hours. They were terrible -- grossly underdone. I also cooked a combination of carrots and string beans in the pressure cooker for two minutes for the carrots, plus another a minute for the string beans, and those, with some balsamic viegar, and they werre pretty good.

In general, I tend to prefer sous vide for veggies, in part because it allows me to add spices that might not be melded when cooking with a pressure cooker. But the much faster cooking when using a pressure cooker is also appealing, even though I have a multitude of sous vide appliances.

Any thoughts as to which works better?

Bob

[DocDougherty]

In general vegetables don't tenderize unless subjected to temperatures above 180°F, so I have given up on sous vide for vegetables. On the other hand I have had great luck with pressure cooking lamb shanks. They do need to be fully immersed in liquid in order to dissolve the connective tissue. Usually I torch two shanks, put in a bottle of cheap shiraz or merlot, a cup of lemon juice, a can of tomato paste, chopped celery, carrots, onions, spices of your choice, and enough broth or water (~2 cups) to cover. Bring up to temperature and pressure cook at 15psi for 40 min. Let it depressurize naturally (~15-20 min). Shred the meat, defat the sauce, serve over (brown) rice.

[EnriqueB]

Pressure Cook steaming (not boiling) and sous-vide are the two methods that possibly preserve most nutrients in vegetables. With some vegetables like carrots and leeks this is clearly noticeable: the sweetness and taste of PC-steaming or SV has nothing to do with the dull value when they are boiled, where many water-soluble compounds are gone. With other vegetables the taste difference is not so evident. Note that for PC-steaming to really work for this retention you must use short times, otherwise the tradeoff between temperature and time will be on the wrong side for nutrient retention...

On the other hand, PC-steaming and SV are on opposite sides of speed and convinience: PC-steaming is fast and simple, SV is slow and requires packing and heating a lot of water. PC requires very precise timing and SV provides ample margins.

Boiling+ice water would be the choice if you care about colour/presentation, but for most home cooking I don't care much about this, convinience and nutrients retention come first. Boiling or steaming, on the other hand, allow easy verification of the doneness, something that the PC and SV make harder.

In summary, I choose:

• Boiling+ice water only when I'm interested in retaining colors
  
• Steaming (non-PC) for vegetables with extremelly short cooking times (e.g. thin green asparagus which only take 2/3 minutes of steam)
  
• PC-steaming most of the time
  
• SV for special applications, e.g. when I want to infuse a given flavour into the vegetables, or when I need to cook many different vegetables together, because putting them at different times in the same bath is much easier than cooking them sequentially with other methods.
  

[Baselerd]

Lamb shanks need to be slow cooked for much longer than four hours. I usually cook them at 62 C for 48 hours (ala MC reccomendations).

Regarding veggies, I find that I prefer sous vide over pressure cooking for most vegetables. It is very easy to produce high-end restaurant-quality glazed vegetables by cooking veggies sous vide until tender (with a little thyme and butter in the bag), and then finishing them on the stove with a little glaze (butter, stock, and salt). Obviously, some vegetables are better suited for sous vide than others - I noticed that root vegetables benefit the most from sous vide. Pressure cooked vegetables are great for purees and soups - but they often have too soft a texture to be served whole (maybe I just need to cook it for less time?). Some vegetables are great in the pressure cooker though - such as cabbage, so I really think it depends...

The only head-to-head I've done before is with carrots. It wasn't a tightly controlled experiment - I simply prepared some carrots sous vide (85 C for 1 hour) with butter and thyme. I also pressure cooked carrots with butter, thyme, and chicken stock at 15 psi for 1 hour. The latter was too soft to serve glazed, but had a stronger (but different) flavor.

Edited February 7, 2013 by Baselerd (log)