Panasonic NN-SD688S 1300 Watts Microwave Oven Reviews
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Panasonic NN-SD688S 1300 Watts Microwave Oven

3 ratings (1 Epinions review)
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Inverted v. Perverted

Mar 8, 2012 (Updated Mar 9, 2012)
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Pros:It's the only microwave in its price point that lets you control cooking intensity.

Cons:The "sensor cook" is hit or miss and the dial is #^$%#% annoying.

The Bottom Line: The technology is superior to the competition, and the results are better for the same price. The only issue is the dial.

Why buy Panasonic microwave ovens? Because they're the only product in this price range that (in my opinion) don't use deceptive packaging. Panasonic's "inverter technology" means their microwave ovens work the way you expect them to work. Most other units selling for under $300 don't
To explain why Panasonic ovens are better, I need to explain how microwave ovens work. Normally you set the timer for, say, one minute and the zapper (it's called the magnetron) bonbards your food with as many watts of radiation as it can generate (for this model, it's 1,300) for 60 seconds.

Now let me ask you a question. What do you assume happens if you set your microwave for 50% power and set the timer for one minute? You'd assume it delivers half as much radiation (650W) for 60 seconds, right? 

  Unless the microwave has an inverter-- a device that lets it vary the amount of electric power being fed into the magnetron-- the magnetron always runs at full power. Since inverters add a few bucks to the cost-- and they can break if they're not properly-made-- most microwaves deliver 50% power by using a timing device that turns the magnetron on and off every few seconds.  So if you set the oven to cook for one minute at 50%, you get full power for 30 seconds and nothing for the other 30.

Mathematically, both methods deliver the same watts: 650 * 60 is the same as 1300 * 30.  But if you're baking a pie and the cookbook says "30 minutes at 350 degrees" would you a stove that blasted it with 700 degrees for 15 minutes and 0 for 15? Me neither. It's like the old joke about the mathematician who figures that if you have one foot in a fire and the other in a bucket of ice, you must be comfortable. Except, in this situation, the joke is on the consumer.

If you think I'm kidding about how this works, put a mug of water in your microwave, set it for 50% power, set the time for 60 seconds and turn it on. On most models, you can hear the magnetron turn on and off-- and you'll usually notice the light inside the oven flicker as it does.

This is the reason why chefs hate microwave ovens and crock pots, and love gas flames and heavy pans. One of the first things they teach you in cooking school is that the key to making good food is applying continuous, even heat at a rate you can vary. The last thing in the world you want to cook with a one-setting-fits-all device with some cheap-o switch turning the power on and off.

Commercial microwaves sold for use in restaurants all have inverters. Panasonic was the first manufacturer to put inverters into inexpensive consumer models.  In July of 2005, when I went looking to replace the commercial unit I bought at a bankruptcy auction, I was shocked to see something available for $150. I wasn't sure how long a cheap model would last, but figured I'd give it a shot (I still have a Panasonic clock-radio I bought in 1988). 

The answer turned out to be "a little more than six years"-- about $25 a year. For what you get, that's a really good deal, and I still can't find a manufacturer advertising inverters in less expensive models.

This model lets you do a lot more than other cheap ovens will. As an experiment, I tried many of the recipes in the book. I wouldn't recommend cooking an omelet with it (on the web site, they cook a turkey), but it's not a lot different than the egg moosh you get on a Mcmuffin. A few iterations from now, these devices might actually deserve to be called an "oven."

That said, I wish Panasonic didn't oversell the capabilities of their models. They have a lot of features, but some of them don't work nearly as well as they claim:

Inverter Turbo Defrost:  
This works almost perfectly. Push the button, select the weight of the item (in tenths of a pound) and press Start. It'll zap the frozen food with 30% power for a duration based on the weight. If the item is over a certain weight, it'll stop at regular intervals and suggest you turn it over.

Most people have learned not to use microwave ovens to defrost-- no matter how low you set the rate, it's always partly cooked and part frozen. If you've read this far, you now know why it's never worked-- there's no inverter, so you get intermittent blasts of full-power. With this oven-- which gives you a continuous 30%-- the food will defrost. 

The only catch-- the preset timings assumes you are defrosting a big, blocky rectangular (which is what most hunks of meat are). For long, skinny items-- a slab of bacon, fish filets, frozen vegetables-- you run into that problem (the tips will be mushy while the center is still cold. I recommend entering a smaller fraction of the weight and keep checking

Sensor Cook/Reheat: The oven has a sensor that detects the amount of steam coming off the food. It uses that data to guess when the food is properly heated.

It works really well for leftovers, soup and vegetables. It's not too bad for meat (again, assuming it's a rectangular shape). It's really bad for foods with high starch content. I like thick-crust pizza and it will turn it into a rocklike substance with molten cheese

The manual does warn you what foods should and should not be used, but at the very end of the section and not strongly enough.

Popcorn: This is hit-or-miss. To use it, press a key to select the weight of a bag of microwave popcorn (it has three options) and then press Start. You don't have to listen for when the kernels stop popping-- Panasonic has studied how long it takes, based on backage weight.

But they're assuming you just bought the package of corn and the kernels are fresh. If you forgot about a package and it's been lying around for a year and the water in the kernels has evaporated or the corn is a little stale, the timing will be wrong.  You'll undercook it-- and if you add more time and don't watch, it'll burn.

The manual has a lot of "shortcuts" (how to melt butter or chocolate, bake potatoes). I agree with some and think others are way off. All I can say is that Panasonic must keep their butter in the freezer because mine melts well before their recommended time elapses.

My biggest gripe with this unit is the dial that is used to select both time and temperature. It's a royal pain in the butt-- a lot more work to set than a keypad and I'm convinced it'll be the thing that breaks before anything else.  I'm docking it a pre-emptive star as a result. 

I am told that there is a model identical to this, but with a keypad and not a dial (NN-SN778).  If you can track that down, I'd highly recommend it over this

Note:  If you think I'm a plant for Panasonic, you can read up on the subject at ehow.com/facts_6818200_inverter-microwave_.html. Except for the decision to put ads for Rachael Ray on the page (she is about as good a chef as Ronald McDonald), I endorse the content in all particulars.

Recommend this product? Yes

Amount Paid (US$): 142

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