I wasn’t surprised to find differences in how meat cooks with sous vide and pressure cooking. I want to know more about the best way to cook other things that I use frequently: beans, cabbage, rice, etc. so I decided to do another comparison. Lentils are something that I do use quite often so I thought that a pressure cooker/sous vide test was in order here too.
I got the inspiration to gr cooking lentils from the Joule app on my smartphone. There was a section on “batch cooking”. Normally since I’m always trying to do single-serving cooking and don’t do well with leftovers I’d blow right by a suggestion like that but I noticed that those batch-cooked lentils could be stored in the refrigerator for 7 to 10 days. That made sense since they would essentially be pasteurized. Interesting possibility for something that I use in as many ways as I use lentils!
Lentils are so quick cooking on the stove top that you might wonder why use a pressure cooker, or why (particularly with the time required) sous vide. One reason is hands off. In the pressure cooker it’s set and forget until done. The same is true of sous vide; for me that can be an advantage when I’m engrossed in writing and index. So, a comparison of the two methods.
Another thing that made me curious about cooking lentils this way was that they were cooked in pint jars. With the brown lentils I had in the house at 185°F for the recommended 90 minutes, plus the additional recommended 30 minutes I still didn’t have cooked lentils. But I thought this deserved further investigation so I went in search of other recipes for time and temperature suggestions.
My first stop was to consider how to cook lentils in the pressure cooker other than just pushing the “beans/chili” button on the Instant Pot (IP) was to look at American’s Test Kitchen’s Pressure Cooker Perfection. Much to my surprise I didn’t find lentils listed as an ingredient. So to other reliable sources for cooking time suggestions: from Forks over Knives website 20 minutes. From Kitchn, 15 minutes. Both recipes calling for natural pressure release.
For the sous vide (precision cooking) I did find lentil as an ingredient and, thus, instructions for cooking in Sous Vide for Everybody (location 3646). The recipe called for black lentils (sometimes called beluga lentils). Most often I use French green lentils (lentilles du Puy) but I occasionally use brown lentils so I opted to use those. At least I felt I was comparing apples to apples in terms of looking at cooking times and temperature since both were for black lentils.
I had already tried using Mason jars the water bath and in the IP so I decided to use a pint Mason for both methods of cooking.. Although I believe that Ziploc freezer bags are probably safe, I have a think about using as little plastic as possible for environmental reasons if I can use recyclable containers like the Mason jars.
As with the meat, I decided to season both batches the same so that the only difference was the cooking method so the lentils were cooked with only salt as seasoning; it’s the texture that I really wanted to know about. From reviewing recipes from several sources for both electric pressure cooker and sous vide I prepared two pint jars each with 4 3/4 ounces of brown lentils, salt and 8 3/8 ounces of water–one for the pressure cooker and one for the sous vide water bath. The pressure cooker was set for 15 minutes and normal pressure and the sous vide for 194°F and 3 hours (range 3-5 hours. Then the wait began.
The jar from the pressure cooker was cooled (it was sealed) and refrigerated until the sous vide lentils were cooked. That jar was also cooled (it was also sealed) and refrigerated. .
For the taste and texture tests, both jars were removed from the refrigerator, unsealed to look at the lentils before reheating. The cold jars were placed in a cold water bath to reheat to 145°F (1 hour and 30 minutes).
Just looking at the two, there was an obvious difference in how some of the lentils cooked in the IP were “blown out”–i.e. exploded, burst open, etc. Not great for use in a salad. No surprise here given what I’ve read about the differences in other legumes cooked in either of these ways.
Tasted before reheating (cold), lentils cooked in the IP were much softer, really almost mushy, OK in soup especially if you wanted to puree some to thicken it a bit. The sous vide lentils were firm, but tender–just what I’d like if they were for a salad or a side. After reheating, there were still the same differences.
The flavor? I’m struggling to describe the differences in flavor–there definitely was a difference. I think part of it was that the IP lentils you started tasting immediately when they hit you mouth; with the sous vide lentils you didn’t really taste them until you start chewing them. Then there was this burst of flavor which seemed to me to be more intense than with the IP lentils. I found it very difficult to separate flavor from the “mouth feel” of the two batches–I think the texture differences affected my reactions.
After this experiment I think I’ll be cooking a lot of lentils with the sous vide method. If I want lentil soup I’ll be turning to the IP. I’ll also add more salt to both.
Some interesting things to explore! A son gôut!