Ever tried making idlis with other pulses?

Have you ever tried making idlis with other pulses than urad dal? I just did.

One of my earlier posts was on the special properties of urad dal that make it particularly suitable for making soft and spongy idlis. In that post, I shared how researchers have tried to find substitutes for urad dal, but haven’t found a simple alternative yet.  Because I had read up all this background research, I expected that idlis made with other pulses would turn out flat or sticky or both. But I was pleasantly surprised with the results!

Regional names of the four Pulses I tried:

Chickpea – Chana dal / Kadala paruppu / Kadale bele

Mung bean – Moong dal / Paasi paruppu / Hesaru bele

Pigeon pea – Tuvar (toor) dal / Tuvaram paruppu / Togari bele

Black gram – Urad dal / Ulutham paruppu / Uddina bele

I took half a cup (85 gm) each of chana dal, moong dal, toor dal and urad dal (for comparison). I washed and soaked them separately in 1 cup (180 ml) of water each for 4 hours. Then I ground them in a wet grinder for 15 minutes, as I usually do for urad dal – by adding 2-3 teaspoons of water (remaining soak water + 45 ml) every 2-3 minutes. 

Here is a stepwise comparison of the four dals, their batters and how the idlis turned out:

Step 1 – Washing:

Have you ever noticed this?  The bubbles that form when you wash dals stay longer than the bubbles that form when you wash rice. When I washed the four dals, I found that chana dal forms bigger bubbles. Moong dal forms a lot of bubbles which last quite long. Tuvar dal loses most of its bubbles very quickly. Urad dal forms the most long-lasting bubbles. These differences are due to the different kinds of proteins present in the dals. Urad dal has a class of proteins called globulins which have excellent surface activity that helps hold the bubbles longer. 

Step 2  – Soaking::

Since I have only one wet grinder at home, I can grind only one batch at a time. And I estimated that each batch would take about 25 minutes to complete grinding (15 min), taking out, checking the volume and weight of the batter. I also wanted to give a 5-10 minute rest between batches so that the grinder does not heat up too much. So, I staggered the soaking start time for each batch of dal so that I can soak all the four dals for exactly four hours before grinding them. 

Here are the dals after their respective soaking times:

Step 3 – Grinding:

I ground each batch of dal for 15 minutes, using the remaining soak water and 45 ml additional water. I added the water in instalments of 2-3 teaspoons every 2-3 minutes. As you can see from the pictures below, apart from urad dal (which we know foams up very well. Here’s why), only moong dal showed some amount of foaming / increase in volume while grinding. 

I checked the urad dal batter’s consistency by doing a float test. Looks like this was a good batch of urad and so, I could have added some more water and fluffed it up even more. But I did not do so, because I wanted to keep the amount of water added to all the dals the same for this experiment. And the other dals already seemed a bit runny. 

Here are the dal batters after grinding. (This is a measuring cup for 1000ml). Notice how moong dal has slightly higher volume that the chana and tuvar dal batters. Urad has the highest volume. 

In the picture at the bottom, you can also see that urad dal batter is the only one which has a ‘soft peak’ consistency and holds its shape, while the other batters seem to spread out. 

Step 4 – Fermentation:

I had also soaked and ground 8 cups of idli rice, weighed the batter and divided it into 4 equal parts. Then I mixed each equal part with each of the dal batters. I took out 250 ml of the batters in glass jars so that we can see the fermentation effects clearly:

Notice how water has separated from chana dal and tuvar dal batters – it is floating on top. They also don’t show much rise in volume, unlike moong dal batter. Moong dal batter has risen almost as much as the urad dal batter, with larger air bubbles. The dal also seems to have risen to the top in a separate layer. Urad batter, as expected, has risen the most and has more uniformly-spread small bubbles, without any visible separation. 

Step 5 – Steaming:

Because of the batter separation and bigger air bubbles, I gave each of the batters a good 1 minute mix with a spoon. I then poured 3 tablespoons of each into separate moulds and steamed the idlis for 8 minutes. 

I expected that only the urad dal idli would rise and hold its shape (because of its unique properties). I imagined that the other dal idlis would turn out flat or sticky or both. I was pleasantly surprised to see how the idlis turned out!

Step 6 – Demoulding:

After cooling the idlis in the mould for 2 minutes, I used a wet flat spoon to demould the idlis. Notice how all the other idlis except the urad dal idli have a shiny surface. They also show large cracks on top. I assume this is because they did not have enough air bubbles to make a large network of connected holes- so the steam (from the water in the batter) had to escape by making cracks on top. What could be other plausible reasons for this?

And here is how the idli moulds were after taking out the idlis. Notice how the chana dal idli has come out clean, similar to rice-heavy idlis. 

Step 7 – Checking the taste and texture of the idlis:

The biggest surprise for me was when I cut the idlis into half and observed their cross section:

It looks like all four idlis have lots of bubbles- not just the urad dal idli. The only difference though is that the holes in the other idlis seem to be much larger. Also, the shape of the idlis tends closer to rice-heavy idlis we saw when experimenting with multiple rice-urad dal ratios.

I tasted the idlis on their own and also with a little ‘gunpowder’ and gingelly oil (flax seed idli podi – let me know if you’re interested in the recipe). 

The chana dal idli is the firmest and has a bouncy texture. It had an okay-ish smell and taste. The tuvar dal idli was firm too, and had the strongest dal smell. I didn’t particularly like its taste. The moong dal idli is actually quite tasty, though it is a bit firm. The urad dal idli is the softest and has the most neutral smell and taste amongst the four. 

Takeaways:

• Though urad dal (black gram) seems the best suited for making soft and spongy idlis, other dals fare quite okay too. Moong dal idlis are especially tasty!
• In this experiment, I used a 4:1 rice:dal ratio and used the same amount of water (2.5X the volume of dry dal grains) for soaking and grinding. But I think the optimal ratio and ideal amount of water is different for the other dals. If I would repeat this experiment for the other dals, I would try ratios with higher proportion of dal and slightly lesser water.