For the intermediate and advanced brewers you may want to read up on Yeast Harvesting and Ranching as a way to reduce your brewing costs and maintain consistency in your favorite recipes. I've also posted What Every Brewer Should Know About Yeast that breaks down the fermentation process into four distinct and easy to understand phases. It's a short read that's packed with information you'll want to go back to frequently so be sure to bookmark it and add it to your favorites.
Home brewers have put an enormous amount of work into researching, formulating and brewing their favorite beer recipes and then publishing them online so that we can follow along and brew some great tasting beers. The instructions for brewing their recipes have also introduced us to the same basic brewing steps used by both home brewers and commercial brewers alike, no matter what size brewing operation we're talking about the basics about sanitization, wort preparation, fermentation, carbonation and conditioning are pretty much the same. While the recipes go into great detail about ingredients including the grain bill, extracts, hops and mash temperature, steeping temperature, hop additions not a whole lot is said about the yeast that goes into the beer. Typically a recipe includes the standard one liner 'pitch and ferment at 70F for 14 days' then bottle or keg as desired. Not a whole lot of information there.
Home brewers have put an enormous amount of work into researching, formulating and brewing their favorite beer recipes and then publishing them online so that we can follow along and brew some great tasting beers. The instructions for brewing their recipes have also introduced us to the same basic brewing steps used by both home brewers and commercial brewers alike, no matter what size brewing operation we're talking about the basics about sanitization, wort preparation, fermentation, carbonation and conditioning are pretty much the same. While the recipes go into great detail about ingredients including the grain bill, extracts, hops and mash temperature, steeping temperature, hop additions not a whole lot is said about the yeast that goes into the beer. Typically a recipe includes the standard one liner 'pitch and ferment at 70F for 14 days' then bottle or keg as desired. Not a whole lot of information there.
That's all about to change and it's about time! I've found out myself from brewing over 100 batches of different beer styles, using many different yeast strains and cells counts, just how much of a difference yeast actually does make in the final beer I drink. I've brewed batches using the same ingredients where the only thing I did different between them was to select a different type of yeast just to see what the beers they fermented tasted like. I've also pitched the same type of yeast but using double the amount of yeast or sometimes fermenting at a lower temperature and tasted the final beer produced to judge the differences in taste and flavor. And the differences are huge in both flavor and taste from batch to batch. I started out pitching the absolute minimum amounts of yeast that I thought would be able to ferment my wort into drinkable beer and now I've ended up pitching nearly twice that amount in all my most recent batches.
 |
| The Health And Vitality Of Today's Yeast Surpasses That Of 10 Years Ago |
The fairly recent availability of high grade beer brewing ingredients has led many celebrated home brewing authors to rewrite sections of their published works regarding yeasts and fermentation times. When it comes to home brewers moving their beer from a primary fermenter to a secondary fermenter what was once considered to be 'Bible' has now been reversed.
Home brew experts John Palmer and Jamil Zainasheff have recently said that homebrewers using the proper amount of today's healthy yeast to achieve good fermentation no longer have to be concerned about autolysis like they used to. In his 'How To Brew - 3rd Edition' John Palmer states "a beer that has experienced autolysis will have a burnt rubber taste and smell and will probably be undrinkable". Both authors agree that fermenters that have a large flat surface area at their bottom will accumulate a thin even layer of yeast cells at the bottom as they flocculate out. This will prevent the yeast from dying off and making your beer go bad.
Enough healthy yeast at the right temperature in a Mr. Beer keg, carboy or plastic bucket should allow the homebrewer to keep their fermenting beer in the primary fermenter for several months. Of course if you are adding hops, fruits or other adjuncts to your recipe you may have other compelling reasons to rack to a secondary. But if you have been racking to a secondary to prevent yeast cells from introducing autolysis' burnt rubber flavors into your beer, you can take it from the experts and rethink your current process.
What a difference a yeast makes....
I soon found out that the types of yeast used to ferment your beer can also make a huge difference in the way your finished beer tastes. Just like hop selection there are recommended types of yeast for different styles of beer as well. Mr. Beer makes it very convenient for us by packaging a pouch of dry ale yeast in with each can of HME we buy from them. I've found that this dry ale yeast is up to the job in terms of being able to ferment recipes that include 3 cans of extract, a pouch of Booster™ and some adjuncts. But there are lots of other readily available yeast types to choose from that influence the clarity, flavor and quality of our finished beer.
Follow The Directions That Ship With Each Yeast Type
I've also brewed several recipes that called for liquid yeast types (smack packs and tubes) or dry yeast types that are best suited for specific beer styles like wheat, stouts or ales. Each type of ale or lager yeast ferments best when fermentation temperatures are kept within their recommended optimal temperature range.
Example: The little packets of Mr. Beer dry ale yeast that ship under the lids of the HME cans have a recommended temperature range of 68-76F, which makes fermentation compatible with the temperatures found in most homes.
Example: The little packets of Mr. Beer dry ale yeast that ship under the lids of the HME cans have a recommended temperature range of 68-76F, which makes fermentation compatible with the temperatures found in most homes.
Doing the 2 step, or how our yeast ferments beer....
No matter which type of yeast we decide to use to ferment our beer they all work in pretty much the same way. I think of this as a 2 step fermentation process, consisting of first the slower moving Initial step followed by the quicker Cleanup step.
The first step begins as we pitch our yeast into wort that's temperature been adjusted to the optimal temperature of the type of yeast we're using. Then we whisk the wort briskly to aerate enough oxygen into it, to get the yeast off to a strong healthy start. Under these ideal conditions the yeast cells will be starving when they wake up and devour all the glucose in sight, this is a good thing. Now is a good time to screw the lid on the fermenter and move it to a location that has a constant temperature, recommended for the type of yeast pitched, for the rest of the fermentation.
 |
| Pitching Liquid Yeast Directly Into Aerated Wort |
For the first several days the yeast will be furiously gorging themselves on glucose and converting it into carbon dioxide gas (CO2) and ethyl alcohol. However some of the glucose is eaten by the yeast and used as food to give them energy and some of it goes into our beer as Diacetyl which in very tiny amounts cause beer to take on buttery, butterscotch or microwave popcorn off flavors. I might enjoy a beer with buttered popcorn but I don't want my beer to taste like buttered popcorn.
This diacetyl or buttered popcorn flavor is more pronounced at higher fermentation temperatures and is kept to a minimum by maintaining a constant temperature closer to the lower end of the yeast's recommended temperature range. Beer that hasn't fully completed the initial fermentation step is likely to have a slick buttery taste to it, an indicator that more time is needed to complete the fermentation.
The second step begins as soon as the yeast have consumed all the glucose remaining in the wort, at this point they will begin to re-absorb the buttered popcorn flavor producing diacetyl from the beer. This point in the fermentation process is also known as the 'diacetyl rest' or 'cleanup', when the fermentation looks like it has completed. During the diacetyl rest cleanup step the yeast now converts the diacetyl into food to give them energy as they remove it from the beer, this is pretty cool.
Now is also a good time to increase the temperature of the fermenting beer a few degrees upward for the last 3 days of fermentation. This will help the yeast complete their cleanup work as the higher temperatures will accelerate the process.
Now is also a good time to increase the temperature of the fermenting beer a few degrees upward for the last 3 days of fermentation. This will help the yeast complete their cleanup work as the higher temperatures will accelerate the process.
 |
| Nothing politically correct about this retro beer ad |
Obey the principal brewing rules...
Always remember to sanitize, sanitize and sanitize your equipment before brewing to eliminate bacterial infections or contamination that can also cause excess diacetyl to be produced. I use One-Step for all my sanitization needs and haven't had any issues with infections. I use it to sanitize my fermenters, bottles, auto siphon, yeast containers and utensils.
 |
| Yeast Need The Right Temperature And Plenty Of Oxygen For A Healthy Start |
Aerate the daylights out of your wort and make sure the temperature is just right for your yeast strain before you pitch it. If you don't have enough oxygen in your wort or if the temperature is too high or too low the yeast will stall and the fermentation will take a longer time to begin. This will cause a ton of diacetyl to be produced during this lag time, more than the yeast can possibly cleanup during the diacetyl rest and you'll end up with buttered popcorn tasting beer.
If your finished beer hasn't been given enough time to mature, or condition, it may taste like green apples or pumpkin. This is caused by excessive amounts of acetaldehyde to be present in your beer. Yeast produces acetaldehyde in your fermenting beer as a precursor to converting glucose to alcohol, if given sufficient time the yeast will absorb it and it will be eliminated from your finished beer.
Preparing Danstar Nottingham Yeast
Nottingham dry yeast is available in convenient 11 gram packets that can ferment up to 5 gallons of beer and is also tolerant of fairly high alcohol content levels. Nottingham's recommended temperature range is 57-70F and it's promise of high attenuation and crisp taste have made it very popular with home brewers.
Rehyrating Dry Yeast Before Pitching (optional)
Nottingham after soaking 15 minutes in 4 ounces of filtered water
I was able to cool the mixture down from 90F to 70F in about 30 minutes using this method. You want to keep within the recommended temperature, using hot water for the soak will kill the yeast.
Add 70F wort and stir every 5 minutes to cool the mix down
After the mix was at the same 70F temperature as the aerated wort I poured it into the fermenter tossed in my sanitized hop sack and twisted the top on.
Pitching the yeast into 70F wort
Yeast Expiration Dates
If you're like me you want to make sure that your beer is made from the absolute freshest ingredients available to you. This also goes for the yeast used to ferment those ingredients into a highly drinkable beer, it has to be viable in order for it to convert enough of the fermentable sugars. For some reason or reasons unknown to me the manufacturers of yeast seem to go out of their way when it comes to printing expiration dates on the yeast they package.
Wyeast With MFG 30Apr2010 Stamped On The Package
I got the lowdown on the Wyeast manufacture date you can read it here on the Wyeast site. It seems the yeast is guaranteed to be at its best when used within 6 months of the manufacture date printed on the yeast package.
As for the Fermentis yeast expiration dates it's a little different than you might expect. The packets I have on hand have '07 2010 LTBEA' stamped on each packet, which means the yeast was manufactured in '07 2008', so for Fermentis the date is the expiration date. Fermentis claims their yeast is viable for 2 years from the date of manufacture, as long as the yeast is stored properly.
As for the Fermentis yeast expiration dates it's a little different than you might expect. The packets I have on hand have '07 2010 LTBEA' stamped on each packet, which means the yeast was manufactured in '07 2008', so for Fermentis the date is the expiration date. Fermentis claims their yeast is viable for 2 years from the date of manufacture, as long as the yeast is stored properly.
2 Packages Of Fermentis Yeast Have Already Expired
Danstar dry yeast comes with a 2 year expiration date guaranteed shelf life if stored properly, either refrigerated or stored at room temperature, although they recommend refrigerating whenever possible to assure even better results.
Danstar Dry Yeast Guaranteed Viable For 2 Years
Pitching Just Enough Yeast
When using my Mr. Beer fermenters to ferment my ale recipes I only need to use half the amount of yeast packaged by the manufactures. Most yeast I buy from my LHBS or on line have been packaged to ferment 5 gallon batches. Splitting a single yeast package in two is easy to do and has almost no risk of contamination as long as it done using good sanitization.
 |
| Two Tubes Soaking In One-Step |
For splitting dry yeast packages in half I bring a cup of filtered water to a good hard boil and let it cool down to 90F. Then I fill two empty sanitized White Labs yeast tubes with water nearly to the top and then pour them into a sanitized bowl. I sprinkle the dry yeast into the water and let it sit for 20 minutes stirring it every 5 minutes after that until if forms a paste. I then carefully pour the paste into each of the two sanitized tubes, cap them and let them sit in One-Step until I'm ready to pitch them.
