Timing is everything. Aeration offers great benefits for your yeast at the start of fermentation, but shortly after, oxygen becomes the enemy. A great beer can turn lifeless as hops character quickly fades and stale flavors such as cardboard, sherry, and rotten fruit take over. Since most homebrew is enjoyed immediately in smaller batch sizes, merely following good habits, such as minimizing splashing during transfers, can keep oxidation at bay through the end of the keg. But if you’re making a mead or a big beer that will need to age, you may need to take some sterner measures. Heavily dry-hopped beers, such as New England–style IPAs, are also fairly vulnerable to losing their fresh hops intensity.
The greatest oxidation threat comes when you move the beer from its safe cocoon in the fermentor to another vessel. Let’s break it down.
Transferring the Risk
When you rack your batch to secondary or to a keg, there are three components: the starting carboy, the destination carboy or keg, and the connection between them. Each one offers a chance for oxygen exposure.