As most of you know, your number of choices here are nearly infinite, so how do you know which is the best one for this?
Well, for starters, an RDA is going to be your number one choice here. They are quicker to rebuild on, have better flavor, and you are not committed to a certain flavor for the period of time it takes you to finish a tank.
Even as RDA's go, you have several different options:
Side Airflow - This seems to give the most well rounded flavor profile. In addition, side airflow is generally more adjustable with the ability to close off a side if necessary, because you are going to want to be doing most of your testing on a single coil. If your RDA of choice is already a single coil setup, even better.
Top Airflow – In my experience, top airflow devices do give great flavor, but they often lack adjustability. Since we likely won't be running a full standard setup, you may not have an RDA suitable for the level of ease of use we are striving for.
Bottom Airflow – In my personal experiences, bottom airflow tends to be very airy, leaks a lot, and just not very strong on flavor. If you have one that you really enjoy and think would work well for flavor testing, then go right ahead. Flavor is subjective and it will give you a better feeling of how certain flavors will taste in your favorite device.
My Personal Choice: Side Airflow - Vaporesso Transformer and Royal Hunter. They are both very smooth, have adjustable side airflow, great flavor, easy to build on, and can run in single or dual coil.
Admittedly, I haven't not tried every single wire on the market, but I can give some insight on to what I have tried.
Kanthal A1 – Generally regarded the the go-to wire. It's safe at higher temperatures (as far as science has lead us to believe so far), easy to use, and has a great resistance - allowing you to do a lot of different types of builds within a reasonable amount of space. However, I find the flavor to be a bit metallic. I love this for long term builds in my atomizers, but it leaves something to be desired when you want to taste the juice, and nothing but the juice.
Stainless Steel (316L) – Also generally considered a safe wire, if you know how to use it properly. Be sure to head over to /r/ECR and do some research if this is the route you decide to take. By far, the cleanest tasting wire I've used to date. No metallic aftertaste. One downside is that is has such a low resistance, it can be difficult to fit your build into your device if you are not trying to go below 0.4 ohms. However, since we are aiming to run a single coil build, this shouldn't be a problem for our single flavor testing.
I have used many other wires than these two, but they don't seem worth mentioning because they are so subpar. Titanium and Nickel require being ran in temperatue control mode, which makes single flavor testing more difficult than it has to be. In addition, while ceramic coils produce amazing flavor, these are known to dangerous to use for their potential negative health consequences and shouldn't be considered at all.
My Personal Choice: Stainless Steel (316L) all the way. Super clean taste. Easy to build with. Can be built into claptons. This wire has quickly won my heart and is slowing being intergrated into all of my atomizers.
Same with the wire, there are a lot of different wicking materials out there, this is just an assessment of the ones I have tried.
Organic Japanese Cotton – Very neutral taste, soaks up a lot of juice, and very inexpensive. As long as I gently wash my hands before handling the material, there is very little to no break in time.
Bleached Cotton Squares – This is the cotton you can find in most B&M's retailing for $4 for (5 PC) 1.5” X 1.5” squares that is white as a piece of paper. The fibers in the cotton are usually non linear or do not reach throughout the entire length of the pad, generating bad juice flow. Has an off-flavor and generally requires a moderate break in time. Grossly expensive in stores, but can be bought from any online vape supply shop for a fair price.
Cotton Bacon – About the same color as the bleached cotton squares, but has little to no off-flavor. Soaks up juice about as well as the organic japanese cotton. The fibers in the material are non-uniform. Requires little to no break in time. Very expensive.
Native Wicking – Some sort of hybrid cotton/rayon blend. Perfectly linear fibers and wicks exceptionally fast. A slight off-flavor requiring a little break in time. Very expensive.
Rayon – Very linear fibers. Rather than expanding when it soaks up juice, like cotton does, in contracts. This minimizes the amount of juice it can hold, which is vital for our flavor testing. Moderate to long break in time, but you must wash your hands before handling. It picks up all the oils and debris from your hands. Fairly inexpensive.
My Personal Choice: All the benefits of the organic japanese cotton make this one a no-brainer. I still have lifetime supply of this stuff, which works out wonderfully since it works so great. There's nothing wrong with the Cotton Bacon, aside from the cost. It works very well too.
Clapton wire is an absolute necessity if you are going to run this option due to its ability to act as a wick and hold juice. Ideal diameter is about 1.5-2mm at 5-6 wraps, no spacing. This setup allows the coil to hold as much juice as possible due to surface tension. With no extra juice or wick to cool the wire off, you want to be around 15-20w. You will get exactly one hit from this setup.
Pros - Very fast tasting method. No need to stop and rewick. Especially helpful if you have a big back log of flavors that need tested.
Cons - Hard to get a good grasp on less potent flavors from the mere whisp of vapor. You'll probably be vaping wire and tasting metal at some point.
Single coil setup, empty slot closed, Clapton wire at 2.5-3mm diameter. Wicking is pre-measured and rolled to fit exactly the length of the wire. No tails on wicks. I'll have about 20 or so wicks prepared before I start testing so I save time. This is my favorite setup. Good for when you get a new order and need to taste 5-20 flavors in succession.
Pros - Allows for a more full flavor than wickless. You get about 2-3 full hits. Quicker to setup than a full wick.
Cons - A little slower than wickless, still does not provide a 100% full vape flavor. You could run it dual claptons with half wicks to increase overall flavor, but then you are making the process even slower.
As the title says, it's a full wick. Use your preferred wire setup, single or double coil. Claptons are still encouraged, but not necessary. Your wick will be providing juice from the well and you don't have to count on the wire to hold all of it.
Pros - Allows for a full, true flavor. Good for analyzing a certain flavor over a longer period of time, perhaps for something more complex.
Cons - Takes a good deal of time to repeat this rewicking process for each flavor. If you don't rewick, the flavor will be contaminated with the previous flavoring.
My Personal Choice: When I have a huge backlog of flavors, I will always go with the half wick method. In my personal opinion, it's infinitely better than the no wick, which is almost pointless to attempt. Even if it takes a little more time, I at least get to truly taste the flavor. If I'm working with a certain range of flavors where I want to deeply analyze each one, I will mix up a 10ml batch of each flavor, and do a full wick method so I can steep it and continue testing throughout the day so I can think on it a bit better.
There are several options for doing your single flavor testing. There is no right answer and it majorly depends on what you are trying to achieve. Most importantly though, just get your single flavor testing done! Once you know your flavors, you can begin to understand how to utilize them in a recipe.