Posted by Geordan Saunders on 18th Feb 2015

There are lots of homebrewers who can turn out a great ale -- who among us hasn't held up a pint of our IPA or stout and thought "Damn, that's a fine beer!" What's far less common is a homebrewer who is able to produce truly great lagers. These beers are a bit of a different beast: to repurpose a tired-if-appropriate cliché, ales are from Mars and lagers are from Venus.



Many of us know the very basic differences that separate ale yeast (S. cervisae) from lager yeast (S. uvarum): ale yeasts are "top fermenters," which means they create a rich, dense blanket of active yeast at the top of the beer, making up a big part of the fermenting beer's krausen. Lager yeasts, meanwhile, are "bottom fermenters," so the active yeast colony flocculates out and settles at the bottom of the fermenter, leaving a far more restrained krausen, comprised of mainly clumps of protein and hop material driven upwards by CO2. However, the functional differences of lager yeast are what cause homebrewers the most distress: the requirement for strict temperature controls, big pitches of yeast, and a cold storage period.



The good news is that brewing a truly great lager isn’t nearly as hard as it seems, as long as you’re willing to do the legwork. Here are the most important things to keep in mind when brewing that will produce excellent lagers every time.



Get a handle on your processes

Lagers are, as a rule, less forgiving than ales – there simply aren’t those big hop or yeast flavours to hide flaws behind. This means you’ve got to be strict in your brewing processes, especially the following:

Use the best quality products you can find – stale malt or extract will be very evident in the finished product

Get a good hot break and keep a rolling boil – this helps both the clarity and stability of your end product

Chill quickly, and if possible, whirlpool – you’re trying for a strong cold break, and a minimum amount of trub carryover from your Brew Kettle to your fermenter. To help ensure a strong cold break, use a kettle fining agent like Whirlfloc



Take your yeast seriously

Lager yeast is a much slower worker than its ale counterpart, and requires approximately twice as many cells per millimeter of wort. It’s also highly temperature sensitive, and requires that you’re ready to keep a tight reign on your fermentation. Pay careful attention to these elements:

Your pitching rates. Underpitching can be far more evident in a lager than an ale. Use a pitching rate calculator (Editor’s Note: I prefer the Brewer’s Friend calculator) and make sure you’re following it. Whether you’re using liquid yeast or dry, it’s not as simple as pouring in a vial or sachet’s worth and walking away – do the math.

Oxygenation. If you don’t have a good aeration or oxygenation apparatus, be ready to shake that carboy or pail like your life depends on it – your lager yeast is going to need every last bit of oxygen you can get into that wort.

Your pitching temperature. Lots of homebrewing literature will tell you to pitch your yeast warmer than fermentation temperature. Not only is this bad advice, it’s stupid. The primary reason this “helpful hint” is given is to encourage an undersized pitch of yeast to reproduce more aggressively, so as to make sure that you’ve got a big enough colony to ferment your beer. However, while your yeast is busily reproducing in the warm wort, they’re creating unpleasant esters that will permanently impact the taste of your beer. In reality, you want to pitch your yeast with the wort 1-2c below the fermentation temperature you’re using, to minimize these reproduction-driven esters. After all, you’re pitching a proper amount of yeast because you used a pitching calculator, so there’s no need to encourage additional, unnecessary reproduction.

Get serious about your cold side handling

Lagers are made or broken after you’ve pitched your yeast. There are a number of different ways to handle fermentation, from the traditional “low and slow” lagering methods to new accelerated methods popularized by homebrew bloggers. Below is a high-level description of a favourite method that works well at the homebrew level, inspired by the “Narziss” or “Tasty” lagering methods:

Pitch your yeast 1-2c below your beginning fermentation temperature Allow the temperature to “free rise” to your set temperature (generally 10-12c). Hold your fermentation at this temperature for the first three to four days, or until fermentation visibly slows. Over a period of three days, raise the fermentation profile 1-2c per day to approximately 15-17c on day three. Once the beer has hit its projected finishing gravity, or the gravity has stabilized and fermentation has ceased, lower the temperature of the beer 3-4c a day until you reach 0c, or as close as possible. Note that during this temperature change, it is likely that the liquid from a 3 piece airlock will be “sucked back” into your fermenter due to the pressure change in the vessel. Considering removing the airlock and placing a balloon over the bung to prevent oxygen from being drawn in. (Editor’s Note: a Universal Bung will ensure that the pressure does not suck the bung into the neck of the carboy, and will prevent the balloon from inflating into the carboy – ask how we know that.) Once you’ve hit 0c, you may “lager” – or, more accurately, “cold store” – your beer for as long as you would like. Additional time at this stage will incrementally improve the final product, up to approximately 3-6 weeks depending on the beer’s original gravity. However, a strong and healthy fermentation will mean that the beer will be ready to drink as soon as you hit your cold storage temperature. Carefully rack to your keg, remembering to purge oxygen from the vessel beforehand. Carbonate using your preferred method and drink when ready. If you are bottle conditioning, store the bottles in a warm (room temperature) location for 2-3 weeks as you would with an ale before returning them to cold storage.

Conclusions

Brewing a fantastic lager isn’t as easy as a great ale, but when it’s done right, it’s a showstopper! A well brewed lager is something any homebrewer can do with just some attention to detail and careful control -- and when you do pull a pint, it will be all the sweeter knowing that it’s not just delicious, but it’s an achievement in brewing!



Wait, I want to spend money on this!

Here’s a few product recommendations for those who’ve got a few dollars to make their lager brewing easier: