What is the best tannin blocker to cover wood

Have you used Zinsser? I've used their Cover Stain (not for tannins - for aged damp mark) and it was excellent. They do a B-I-N product for tannin stains too. I think their BIN products are oil based but can be painted over with water based paint.

Hi
I had a look at the Zinnser range today and Kilz 3 I need to make a decision as I am hoping to paint all the wood this spring. If you have used both of the above which would you recommend?
I am assuming when you use the blocker you do not sand afterwards before painting the top coat.
I will be using an eggshell finish.
Any advice would be helpful as I don't want to have to repeat all this process again.
Thank you

I haven't used Kilz. The Zinsser Cover Stain I used was an aerosol, it was extremely easy to use - l was using it on ancient water marks on a ceiling. It says it can be used for tannin stains. You don't need to sand it and it's quick drying.
I've also got a house with all the woodwork leaking tannin from knots. I suspect none of it was painted properly after a post house fire total refurbishment years before we bought it. I hate painting woodwork! I'm also worried that the tannin will reappear so interested to know what you decide. I'll see if l can find out any more info.

Old frill
That is exactly what as happened to my paint work. When it was new wood the decorators treated the wood before painting but over time the tannin showed through. It as continued to show through the paint over the years and I have continued to touch the dark ring up before painting. I am so fed up with doing this because it takes so much time to treat and paint all the architraves.
I am going to try the Zinsser as you recommend and hope it will cover.

How long did it take before the tannin broke through last time? Please let me know how you get on.

It's hard to remember but I'd say at least two years. I'll use the blocker again this time and top coat but that's the last time, I'm getting too old to keep painting. We are not painting the ceiling or coving they look ok I'll give them a wash with a long handled sponge. I get nervous about even painting the walls standing on steps but it as to be done. I'm alright painting the skirting and doors, I'll start sanding next week, I want to get it started before the weather improves and the garden takes off.