Noob here. is there a limit to how long you can ferment or how many times you can do it with one beer? i keep hearing "secondary fermenting." does this make a difference in the beer? and if so what happens if you age longer or shorter periods of time?
"Primary Fermentation" = the first / main fermentation of the wort you produce on brew day. It is done in a "Primary Fermenter" aka the first vessel you choose to fill with wort on brew day and pitch yeast into. The vast majority (if not all) of the alcohol in your final beer is made during this phase. A majority of the alcohol produced during primary fermentation can be made in as little as 2-3 days, while sometimes it can take 1-2 weeks. After the alcohol is produced, the yeast still does additional work to improve the flavor of the beer. For that reason, most styles of beer remain in the primary fermenter for 2-3 weeks. Some beer styles, mainly wheat beers and low alcohol beers, are only kept in the primary fermenter for 1-2 weeks. Other styles, typically very high alcohol ones, are kept in the primary fermenter for an upwards of 4 weeks. Make sure you note whether people are saying they actually secondary fermented the beer or whether they just transferred (aka "racked") the beer to a secondary fermenter, when reading any mention of the term secondary with regards to brewing. "Secondary Fermentation" could either be done in the "Primary Fermenter" or a "Secondary Fermenter" and would involve adding additional fermentables (sugar sources yeast can eat / aka ferment) to the beer after the "Primary Fermentation" is complete. This "Secondary Fermentation" will increase the amount of alcohol in the final beer. It can be done several times actually, but it requires yeast that are very healthy. Also note that each yeast strain has it's own alcohol tolerance level. So once the beer reaches that threshold, the yeast will no longer ferment any additional fermentables you add. The process in itself is not inherently beneficial to the flavor of the beer. Depending on what type of fermentable to choose to add (various forms of sugar, fruit, etc) it can alter the flavor of the beer. Sometimes in desirable ways, sometimes not. A "Secondary Fermenter" is a second vessel that some choose to transfer the beer into after the "Primary Fermentation" in the "Primary Fermenter" is complete. It's an optional step that most modern homebrewers choose not to take. The negative of doing this is that the beer could possibly come in contact with oxygen during the transfer, which would cause it's flavor and aroma to dissipate / age faster. The positive of doing this is that 99% of all beer styles shouldn't be left on the cake of trub (composed of flocculated live yeast, dead yeast, coagulated proteins, and sometimes hop debris that settles at the bottom of the "Primary Fermenter" over time) for extended periods of time (say more than 4 weeks as a generally) or off flavors could be developed in the beer. Another positive of transferring beer from the "Primary Fermenter" to a "Secondary Fermenter" is that, when you are ready to bottle the beer, it will help a newbie will have an easier time getting beer with less particulates into the bottle. Since a beer transferred from a primary fermenter to a secondary fermenter is now off of the yeast cake / trub pile, it can be kept in the secondary fermenter for a much longer period of time than a primary fermenter. Some styles that require/benefit from extended conditioning will make use of a longer wait in a secondary fermenter. Russian Imperial Stouts and Barley Wines often do so at temperatures closer to their fermentation temperature or at "cellar temperatures" closer to 55F. Often these styles are left in secondary fermenters for 6-18 months. Lagers and Kolsch biers often are "cold conditioned" or "crashed" to near freezing temperatures and stored for extended conditioning periods (generally 1-3 months) in secondary fermenters. Most styles do not benefit from extended periods of conditioning in secondary fermenters, since they reach peak flavor sooner and begin to degrade shortly after that. Hoppy beers, wheat beers, and beers low in alcohol tend to reach peak freshness the quickest for example. I highly recommend that you go to www.howtobrew.com and enjoy the wealth of great free information it has to offer. It's a free streamlined version (but it isn't as up to date as the newest book versions) of John Palmers "How to Brew" book, which is considered by most to be the best modern book for homebrewing basics. Welcome to the hobby!
What he said. The long and short is: for most beers, all fermentation, clearing and aging can be done in your primary fermenter. If you want to get technical, when you prime and bottle, that conditioning is a secondary fermentation (there is added sugars that the yeast will eat, producing the CO2 that carbonates your beer) Most of us agree that there is no need to rack most beers to a second fermenter (bucket, carboy, etc) unless you are planning to bulk age with fruit, maybe wood (oak aging, for example) or souring agents. For small batches, it's just not worth the potential for oxidation, contamination, and a couple more -tions that sucking the almost-finished beer out of one bucket and into another one that the plus side would provide (mainly clearer beer, which IMO doesn't really matter unless you plan to enter into a competition.)
One more consideration for not conducting a transfer from the primary to a secondary: you eliminate one more point of potential infection. And yes, bottle conditioning = secondary fermentation. Cheers!
