Friday, January 16, 2009

Pitching yeast into your homebrew

Yeast StarterHere are some tips about getting the most out of your ale yeast. After boiling, once your wort is cooled down to about 70 degrees it's time to take the batch to a cool location and pitch the yeast. In most cases, it's a good idea to make a yeast start ahead of time (1-2 days earlier) to help ensure there are plenty of yeast that are ready to go to work immediately. (See Making a Yeast Starter.) Having lots of "awake" yeast can help prevent infection from getting into your beer.

If you are using a yeast starter, gently swirl the starter to get the yeast separated a bit then pour it into your cooled wort. If you are using a pouch or vial, ensure it's been warmed to pitching temperature first and is activated before pitching. I'm a big believer in giving my beer a healthy dose of as much yeast as possible to ensure a strong and quicker start to fermentation.

Aeration: One of the most important steps to ensure a good fermentation is providing for an adequate aeration (oxygenating your wort). You can do this in many ways. One simple way is to shake up your wort for several minutes to aerate the wort. Boiling takes out most of the oxygen in your wort and yeast need a lot of oxygen to survive. If you happen to have an oxygen tank and a bubbler (for an aquarium) you can put a sanitized air hose into the wort and bubble it full of oxygen for about 30 minutes.

Once aeration is complete, then add an airlock and/or sanitized blow-off tube to your fermenter. In this example below, I used a food-grade plastic container and a 3-piece airlock. Be sure to sanitize every piece of equipment you use ahead of time to help prevent unwanted bacteria from getting into your beer.

After a half a day after pitching your yeast, your airlock or blow-off tube should be going nuts with activity. If so, your brew is fermenting strong! If you don't see much activity after a day or so you may have under-pitched your yeast or perhaps had your wort at a too high or low temperature.

Ale yeasts tend to do well between 65 to 74 degrees. Any higher and your yeast may produce esters that can give off flavors or aromas. Any lower and fermentation may go very slowly or perhaps make the yeast dormant. Lagers work at colder temperatures around 45 to 50 degrees and take much longer to ferment. Refer to your homebrewing guides for details on lagers as we are dealing primarily with ales in this example.

In my most recent batch example, the fermentation was strong within 10 hours after pitching and went nuts for about 3 days after that. It then seemed to be complete by the end of the 4th day. Note, however, that just because you don't see much activity in your airlock or blow off tube doesn't mean it's done fermenting. Sometimes it's good to gently agitate the fermenter periodically to get some of the yeast off the bottom and into the middle. Your ales will probably be fermenting for at least 10 days. When in doubt, take periodic gravity readings and after a day or two the readings stay the same then you can assume the fermentation is complete.

Typically, you should let your brew sit in the primary fermenter for at least 1 to 2 weeks and then optionally rack it into a secondary fermenter for settling a few days and then I'll get ready for bottling / kegging day. Don't worry, letting your beer sit on the yeast cake for several weeks shouldn't affect your beer. Racking to a secondary does risk putting oxygen into your finished beer and that can lead to off flavors. Remember, you only want to aerate / oxygenate unfermented wort, and not after it has finished fermenting.

Here's a video of a yeast pitching session. You might wish to aerate a lot longer than I did in this example. The more oxygen mixed in up front the better.



It's OK to aerate either before or right after pitching your yeast. The yeasties don't mind getting shook up provided the wort is at a good temperature. My yeast survived just fine being pitched before aerating.

Be sure to read all of the comments below from other homebrewers. They have a lot of good tips to add. Feel free to add your own comments on this subject.

Continue reading: Homebrew batch transferred to secondary.

Related articles:
- Creating a yeast starter for homebrewing.
- Making an extract homebrew - 1st of the year.
- Testing a Blichmann Boilermaker brew kettle.
- The trials and tribulations of bottling beer.

This article came from FermentedlyChallenged.com
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