This Wine Aerator Decanter, when a bottle of wine is poured into it, whisks it and helps in getting more molecules of the liquid come in touch with the air. Most of the decanters are seen with a roomy bowl which allows more wine to get in contact with more air. More room means more air available in the bowl to get in contact with the wine.
The aerators are a bit different from the conventional decanters. These aerators have fancy funnels which help you to use only a glass of wine at a time and store the rest of the bottle for later use. This is in a way an advantage as the wine exposed to air, if left for more than a few hours makes it flat and sour. So it is better to expose the required amount of wine only.
Some aerators are designed such that as liquid flows into it, there is a provision to draw air. So, required amount of air is drawn dynamically depending upon the quantity of wine. Such aerators work well with either old wines or younger wines. These actually work the best with red wines which have a characteristic of improving when aerated. This of course can be identified with close observation. If you give aerated and non-aerated wines to beginners you can observe that they would like the aerated ones without knowing which one is what.
You can say that this effect can be obtained by just whirling the wine in the glass. Of course you can as it can be considered as the poor man’s aeration. It is actually similar to whisking cream or beating eggs manually with a spoon, but if you whisk it with a beater you would get an improved result. In a similar manner if you use aerator the effect what you get is quite different from normal swirling. The wine aerator will be different for white wines and red wines to keep the difference of wines intact.
The mechanism will be the same. Anyway the difference in flavors before and after aeration is very minute as we said earlier and can be identified only through close observation. So if you ask the question “are wine aerators really necessary?” then it has to be left to the individual’s interest. If you really find the difference and want to enjoy every sip of your wine then may be it is a right choice. So finally the answer to this question depends on the one who wants to have the best experience of drinking wine.