Juniperus plant species contain condensed tannins. We've done a lot of work with total CT, etc., but I've not been able to find anyone who's analyzed the MW of them.
The analysis of CT is the most challengening approach in phenolic compound chemistry. As the variation of the single compounds and the multitude of reacting with each is that big, identifying and quantifying single compounds is very difficult. One can try MALDI-TOF-MS to get an overview of the distribution of the molecular weight....or GPC...but also in both methodologies the potential huge variation from comparatively small CT to the really large ones, can be a challenge...