Well, I look at the varietal first and the characteristics of the aglianico. Then I look at yeast descriptions. Morewinemaking.com really has the best descriptions on this. I figure out which characteristics I want to enhance...ec118 that comes with it has a description that reads something like a neutral flavor component that will do the job with no problems in a super wide temp range. (Ideal for kits)
While let's sat the bm 4x4 Jim is looking at is described this way...BM 4x4 is a new yeast blend created by Lallemand, designed to provide all of the benefits and flavors of the BM45 yeast strain, along with a much more reliable and consistent fermentation. This means that you'll be getting all of the flavors of jam, rose petals, and cherry liquor with a stronger fermentation with less risk of a stuck or sluggish fermentation. This is a blend between the traditional BM45 and a complimentary strain, chosen for its fermentation kinetics. Positive interaction between these strains means a more dependable fermentation, along with increased aromatic intensity, color intensity, and length of finish. Ideal fermentation temperature is between 64-82°F. This strain will enhance varietal character, and mouthfeel in a wine. Alcohol tolerance is 15%.
And the Rockpile RP-15 I'm considering is described...RP-15 is a recently isolated Californian strain that was selected from spontaneous Rockpile Syrah fermentations by Vinquiry in collaboration with winemaker Jeff Cohn. RP-15 is a moderate rate fermenter with average nitrogen demands. Due to its' ability to develop a structured yet lush and balanced mouthfeel, RP-15 is ideally suited to making rich, concentrated reds. Initial winemaker feedback has indicated that RP-15 does well with emphasizing varietal flavor and red fruit character. In addition, with careful hydration and nutrients, RP-15 delivers good mineral and spice notes to wine. RP-15 is recommended for Syrah, Zinfandel, Cabernet Sauvignon and Merlot. Best results from 59 to 90 degrees F, with an alcohol tolerance to 16%....
I done well over 20 kits and dragons blood ( thanks Dave) which has helped me learned about feeding my yeast and stuck fermentation, so I feel like if I had a problem I could solve it. And of course this voids your warranty with your kit.
Ps descriptions totally plaguerized from morewinemaking