Making Vanilla Extract

Back in August I read this blog post and decided to make my own vanilla extract.  It sounded so easy - just throw the stuff in a jar, stick it in a cupboard for a few months, and voilà, vanilla extract!

The vanilla beans I ordered online were a great deal, and I've been able to add fabulous flavor to marshmallows and various baked goods with them.  

The extract, on the other hand, is taking a little longer than expected to produce results.  While the instructions I followed at the top link above said that the initial concoction of alcohol, store-bought vanilla extract, and vanilla beans should produce a useable extract after 6-8 weeks, I found that it was rather weak.  Well, weak on vanilla - but still very strong on the alcohol!  I have used the extract in a few baked goods since October, but only when I knew it would not greatly affect the outcome.

This slow development of my extract may be due to the slow rate at which I am adding vanilla beans as I use up their seeds in other cooking projects, but I have a feeling that this would not account for the still very powerful alcohol content that was supposed to have faded by now.  I have used a combination of vodka and brandy in order to develop a more complex flavor, but perhaps they have just strengthened each other's resolve to dominate the jar...

I will continue to add beans to the jar and let it sit in my cupboard, but I would love any tips about how to assist this development.  As I read online, this would make a great gift, and a continuous supply of vanilla extract would be immensely practical, but I'm still pretty far from that goal...any helpful ideas?