Crock-pot/slow-cooker basmati sushi/ketupat

Question

I have successfully made sushi rice or ketupat cakes with long grain basmati using the slow cooker. I see the advantage that I could use fragrant or any usual household rice rather than sticky rice.

It takes about 3 hours to get sticky basmati sushi rice, and about 4 hours to get ketupat rice. I have even made biryani ketupat embedded with shiitake slices.

The ketupat rice would need to stand for a couple of hours to fuse into a rice cake. Right now, I need to use a knife to cut up the single big block of ketupat rice cake. I am racking my brains what type of dividers, and how, I could put in to produce small blocks of ketupat. Because cutting and digging out the rice cake causes it to break apart.

I have been scouring the WWW to find if there are people of similar adventure to mine in using the slow cooker and non-sticky rice to make sushi rice or ketupat rice. They must be so extremely rare that I am unable to find them to learn from their experiences.

The incidence of burning the rice is very low since the slow cooker cooks very slowly. It did get burnt once when I had forgotten all about the pot for 24 hours.

As far as I could judge, the basmatic rice is just as sticky. In fact more sticky, while still retaining its individual rice granule shape.

Question:

I am asking these questions because I am concerned that the rarity of the practice might be due to the resultant quality.

Are there disadvantages in quality of resulting rice when using the slow cooker versus using a rice cooker, that I need to know? Otherwise, why aren't people using the slow cooker for this wonderful purpose?

Besides training myself for the right amount of water and avoiding burning of rice, what are the pitfalls I would need to avoid in my continuing this route.

Would slow-cooking destroy taste or scent quality of the rice.

Answer 1

Traditional sushi rice ("meshi") is defined by both the stickiness of its rice but also its lack of gumminess. Each grain of rice is supposed to remain distinct. The final component of sushi-meshi is of course the application of vinegar, which is supposed to evenly coat the outside of every grain. Proper application of vinegar is not possible unless the grains remain distinct. Therefore, if the rice is overcooked or cooked too slowly, water will have more time to penetrate and the starches will have too much time to swell, causing it will turn into a sticky mess with indistinct rice grains. Furthermore, basmati rice can't be used for traditional sushi-meshi because it doesn't have enough amylopectin (the starch in rice that makes it sticky/"glutinous"). Glutinous rice (which has 100% amylopectin and virtually no amylose) is used for ketupat but isn't used for sushi-meshi, since it is too sticky.

There is nothing culinarily wrong with using a slow cooker to make rice; if it tastes good, eat it! In fact, a quick web search reveals many recipes. Here is also an answer to a relevant question. But I don't see a way of making sushi (for which there are relatively strict traditions and definitions) using a slow cooker.

Edit: To answer your specific question…

Would slow-cooking destroy taste or scent quality of the rice?

The distinct aromatic scent of basmati rice comes from 2-Acetyl-1-pyrroline, which is also formed from the Maillard reactions. Since the Maillard reactions happen at a much higher temperature than that at which your rice cooks, I would guess that those flavor compounds would not be harmed by using a slow cooker.

Edit #2: According to this study, 2-Acetyl-1-pyrroline is highly volatile and absorption in rice can be hindered by excess water and/or long cooking times. This suggests that using a slow cooker to prepare basmati may produce less aromatic rice than using a quicker, dryer method like steaming. As an interesting side note, the study also suggests that this aroma can be intensified by adding pandan leaves while cooking the rice.

Answer 2

A rice cooker uses higher heat and much more quickly....it uses high pressure as well, so steams AND boils at the same time. You DO know that the proper rice is a VERY short grained rice grown especially for sushi, right? having said that, I recently learned that it can be best to soak rice a half hour or so before cooking. I no longer own a rice cooker, but use a regular pot. I cook it quickly, then when it is or 2/3s done, I turn the burner off and leave the pot on the electric burner - some times, if 3/4s done, i simply remove the pot from the burner and let it steam in the pot for a while. this is esp. easy now that i use a ceramic pot that retains heat better than metal.