I have a question regarding "blow-off tubing". I recently finished reading the book "Brew Chem 101: The basis of homebrewing chemistry" and learned about the off flavor called astringent which is a direct result of polyphenols (or tannins). The book states that one way to avoid tannins is to separate krausen from the fermenting wort via a blow-off tube. I have brewed over 9 homebrews and only once used a blow-off tube to remove the excess CO2 from the fermenting carboy. The one time I did use a blow-off tube it was for the first 4-7 days and then I capped the fermenting carboy with an airlock. Would you recommend always using a blow-off tube during the first few days of fermentation or does the use of a blow-off tube not really necessary. Also, does the blow-off tube actually remove more tannins from the Krausen than an airlock? Please let me know at your earliest convenience. Thank you for your time.