I want to make cider from pears. Right now I'm looking at buying a few kg of Abate Fetel (I think that's what they're called), because those are the cheapest pears by a factor of 3-4 right now. The ones I bought don't taste like much, but they need to ripen some more. What I can tell alreday is that they have a bitter note, I assume that's the tannin. What I want to know if this pear makes a good cider.
The preferred choice of pears for making cider (or "perry") are collectively known as "perry pears".
'Abate Fetel', AKA 'Abbé Fetel', does not fall into this group. Abate Fetel is commonly described as "more sweet" than many other varieties, and because of this it is popular as one to eat rather than use for cider. The bitterness you tasted is more likely due to the unripened state if they are truly of this variety.
However, for a price as good as you are talking about, I would at least consider giving it a try despite it not being one of the preferred varieties.
The fact that they're known to be very sweet can, according to one study I found (http://extension.wsu.edu/maritimefruit/pages/perry.aspx), imply other properties about it that may be useful in tailoring a recipe [if you decide to do so]. For example, the sample seems to suggest that "sweet" is correlated with "low acid [and] low tannin".
I think the sweetness also allows one to assume a relatively high concentration of sugar in the pears, something else you would definitely want to take into consideration if you decided to try it.
In Summation: Unfortunately the short answer is that it's unlikely to be spectacular, so depending on your investment, expectations, opportunity cost, and other factors, you may want to shell out the extra money for one of the varieties that is on the list: