In's and Out's of Brewing Lagers

What is a lager beer, really?  This term covers a wide variety of styles and types of beers, but what makes a lager a lager?  When it comes down to the nitty gritty, down to the yeast we use for this wonderful sport we all engage in, there are two types.  Ale yeast, or top fermenting strains and lager yeast, or bottom fermenting strains. This week, we’ll cover the aspects of brewing a lager, the process of lagering, or cold ageing, and what the differences are between the two types!

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Ale and Lager Fermentation

Fermentation is the most important part in this whole sport.  I’ve said many times that, as brewers, all we’re doing is making delicious sugar water.  It’s our yeast that really do the work to make all the magic happen. It’s how they do the work, and within what temperature range they do the work, that makes all of the difference, and decides whether our beer is an “ale” or “lager”. 

Ales, which cover a huge majority of styles of beer, especially for homebrewers that don’t have fermentation temperature control.  The range on ale yeast is 60° F to 75° F, depending on the strain, although there are some, like Imperial Loki, that can ferment cleanly as high as 95° F!  These are typically considered “top fermenting” yeast, which just means that it tends to climb towards the top of the beer while it ferments.  Most beers that you both make and drink will be done with an ale strain because they are fast fermentors, comparatively, and tend to easily accentuate hops, malts, or both.

Lagers tend to be a little bit harder to wrangle.  Fermentation temps drop into the 46° F to 55° F range, and, at least on the homebrew scale, primary fermentation time doubles from 14 to 28 days.  This is a HUGE time commitment for those of use who are trying to bump out an ale or two every month, and if you only have the one fermentation chamber, you are stuck until it’s done.  Lager yeasts are called “bottom fermenting”, again because that’s where they like to work. While there are plenty of craft lagers on the craft beer market, you can generally tell the good from the bad because most lager beer, though not all, is light, easy drinking, and there’s not a whole lot of other flavors to hide behind.

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The Lager Fermentation Process

Just like with any beer, we start from the yeast and work our way up.  When doing a light American or European lager, we like to look at how the yeast act, what they accentuate, and how to best build the recipe around their particular profile. 

Lagers need to be fermented at cold temperatures.  It’s a fact of life. Because of this, your cell count needs to be WAY up.  As much as 2 or 3 times as much yeast as you pitch into your ales, depending on gravity.  This is because everything is happening S.L.O.W.L.Y. To the point where eating the sugar and conditioning the beer happen at the speed of pouring molasses cold.  To get a clean and healthy fermentation, they need plenty of cells to do the leg work, otherwise they can get overwhelmed and crap out on you, leaving off flavors in the finished product.

Another really important part of brewing lagers is the diacetyl rest.  By the book, you’re looking at the last 4 days of fermentation at least 4° F higher than fermentation temp.  This kind of forces the yeast to finish the clean up process without stressing them too much to do it. This ensures that yeast derived off flavors stay out of your lager, but doesn’t make any more. 

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Lager Fermentation VS. Lagering

A common misconception when brewing a lager beer is that fermentation is “lagering”.  Lagering is the process of cold storage to get all of those sulphur compounds out of your lager.  Lager fermentation is fermentation at lower-than-ale-temps, usually 47° F to 55° F. Don’t get confused!  “Cold Brewed” is not actually a thing!

Most delicious and solid lager yeast strains tend to produce more sulfur compounds, which is something that you can’t really get around.  It’s a part of the yeast, and just kind of how it goes. The key is long term cold storage, which helps the sulphur break down and bow out of your beer.  This may not be super necessary for beers like doppelbock or Baltic Porter, but it’s a MUST for lighter American and European lager styles.

To be fair, this is a traditional lager technique, and for most commercial breweries, this isn’t as important.  One thing that we have to remember is that with conical fermentors, the pros and some lucky homebrewers, are working with increased surface area, so they can get away with decreased lager fermentation times because more yeast is exposed to the wort, and therefore doing more work to get off-flavors absorbed and eating up general bad-ness.  For most of us homebrewers, we’re in buckets, carboys or general available fermentors, so we don’t have that surface area to “fast lager ferment” our beers. This is why we always recommend such a long (and painful) fermentation period to get your lagers right.

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Yeast Strains

Lager strains are brilliant and varied, just as you’ve come to expect from ale strains.  Even though they work differently, they are no less easy to predict and use when you have all of the right equipment.   But what about when you don’t have the right equipment?

Luckily, there are some tried and true lager strains that work well at ale temps, and they are, of course, as varied as the rest.  If you want to try out a lager, but don’t have temp control, then try some of our favorite strains!

  • Imperial Loki - definitely and distinctly an ale strain, but produces killer lager like characters at 64° to 70° F
  • White Labs Cry Havoc - WLP862 is a killer strain that leaves your beer clean, crisp and lager like up to 70° F.  Thank you Charlie Papazian!
  • Imperial Cablecar, White Labs 810, and Wyeast 2112 - This common hybrid strain is the most well known hybrid strain, known for Anchor Steam’s classic California Common, a beer that created a whole style.  Clean, crisp and accentuates hop bitterness.

Whatever hybrid strain you choose, they all do really well and make awesome, lager like beer.  Less sulphur and cold conditioning is required, and they make life a bit easier. You can also try classic lager strains at ale temps, although be prepared for wild differences from strain to strain.  We’ve tested Imperial Harvest, and it tends to be amazing, as well as S-23 from Safale, but some of the rest are up in the air!  Test them out and tell us what you’ve found!

Thank you for reading!  Post any questions, comments or experiences below so everyone can grow from your fermentations!  Don’t forget to catch up with us on Facebook, Instagram and Twitter to keep up on everything that’s going on!  Check us out on YouTube at BrewChatter TV, and keep reading BrewCranium!  Sign up for our mailing list HERE so you know when new articles and videos come out, as well as killer sales new product updates!  Brew On!
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