Archive for September, 2012

Lager Week, Day 5—Yeast Breeding

As we mentioned on Day 3, one packet of yeast is not enough to make lager. Instead of buying several packets, I recommended using a yeast breeder. In homebrew parlance, this is called a “starter.”

 

Starters are easy to make. I have a two-gallon bucket fermenter I got at my local homebrew store. It fits a standard primary airlock. (“Das Hefewerk” means “the yeast factory” in German.) I use 1.5 gallons of water and 2 pounds of light liquid malt extract to make the starter*. All you need to do is heat the water and stir in the malt extract until it dissolves completely. It is not necessary to do a boil, because you’re not doing a hop extraction, but you do want to pasteurize the mixture to reduce the bacteria present. According to the pasteurization tables, all you need to do is get the mixture over 160 F for 15 seconds. I like to play it safe and I take it up to 190 or so, but that’s almost certainly overkill.

Chill the wort under 80 degrees, pour it into your yeast starter. Add the full vial or packet of yeast, just like you were making beer, and pop the lid on. The yeast will start fermentation shortly, and begin reproducing, which is what you want!

The temperature is still important, so keep your starter near the fermentation temperature you intend to use.

Two days before you plan to brew**, move the starter into your refrigerator, at normal food storage temperature. This will knock your yeast out, and cause them to settle to the bottom.

On brew day, you want to prep the yeast about 3 hours before you will need to add it to your beer. Handle your starter carefully to avoid mixing it up. Open it, and gently pour the liquid off the top, leaving your yeast cake in the bottom. Get as much of the clean liquid out as you are able without losing any significant amount of yeast. Leave just a small amount covering your cake so that it isn’t exposed to the air.

When it’s time to add yeast to your beer, add about a quart of clean water to the starter, swirl it around to get the cake all mixed up in the water, and dump the whole thing into your primary. Voila!

Yeast Starters really kick your fermentation into high gear. I use them with all my beers, not just lagers. When I pitched one vial in a five-gallon batch, I often had to wait 24-36 hours to get a visible fermentation. With a starter, I typically get visible fermentation beginning within 3 hours. That’s awesome, because once the yeast start really going, they muscle out bacteria, and it keeps my beer clean.

When you’re done, you want to kill any leftover yeast so you don’t wind up breeding hybrid Oktoberfest-abbey ale yeast or anything like that. Fill your container with a mixture of 1 cup of bleach per gallon water and let it sit for a minute. Don’t forget to clean your lid.

I love my yeast starter. Since I started using it, I have had no problems with stuck fermentations or infections. I can’t recommend them highly enough.

* If you’re using a one-gallon container as a starter, use 1 pound of liquid extract in 3 quarts of water. You need headspace, or you’ll get a beer geyser! A smaller starter will mean you generate fewer yeast cells. You can also use dry malt extract. Use about 10 percent less by weight.

** If your brewing is delayed, you can still use your starter. Keep it in the fridge until the day before you brew. Then, pour off your clean water as described above, and add it to 1 quart of water, with a quarter pound of malt extract in it (cooled to below 80 F, of course.) Let that sit overnight to wake up the yeast, and pour the whole thing, extract and all, into your beer when it’s time to add yeast.

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Lager Week Part 4, Diacetyl—What it is and how to deal with it.

Diacetyl* is a natural product of yeast, and it tastes buttery. In fact, it is added to artificial butter flavorings to give them their characteristic taste. Needless to say, you don’t want it in your beer any more than you want to float a pat of butter on your foam when you pour.

While the yeast is in the rapid fermentation stage, it is growing and reproducing rapidly, which requires it to make lots of new proteins. Diacetyl is produced in the process of building those new proteins. (Those hoping for more technical information should go read the wiki.) When the yeast is growing quickly, all that diacetyl leaks out of the cells and into the beer. As the fermentation slows down, the yeast will reabsorb all the diacetyl and use it to make more proteins, so in the long run, the beer is diacetyl free.

The cool temperatures of lager making slow all of these chemical processes down. While ale yeast will mop up the extra diacetyl very quickly, so that you rarely have to concern yourself with it, lager yeast may drag their feet a bit. Cold lagering will stop fermentation completely because cranking the temperature down into the 30s will knock out the yeast. If you stop fermentation too soon, you may wind up trapping diacetyl in your beer. You want to check your beer for diacetyl before you drop the temperature at the end of secondary fermentation.

The other sneaky thing about diacetyl is that your beer may have chemicals that aren’t diacetyl yet, but they will be someday. You don’t want those either. Those can be converted to diacetyl instantly at about 180 F. But of course, you don’t want to cook your beer!

So, here’s what you do. Open your carboy and take a small sample of your beer with a wine thief. 2 or 3 ounces is plenty. Microwave it until it starts to boil a little, but don’t boil it all off! Now all of your pre-diacetyl molecules are diacetyl. Let it cool to a safe temperature and take a sip. Warning! This is going to taste terrible! Cooked beer is gross! But, you’re specifically looking for butter flavor. If you taste any butteryness, you have diacetyl that you need to deal with. If the beer is butter-free, you are ready to drop the temperature and begin lagering.

If you have diacetyl, you’ll need to do a diacetyl rest. Bring the temperature up to the mid 60s to speed up the process of absorbing the diacetyl into the yeast. Don’t worry about making esters—at the end of secondary, there’s not much sugar left to do that with. Repeat the diacetyl check every 24 hours until the butter flavor is gone, then drop the beer to the 30s. You should be diacetyl-free in no more than 3 days.

* You can pronounce this die-uh-SEAT-uhl, die-uh-SET-uhl, or di-ass-uh-TEAL. The last option will make you sound British.

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Lager Week Part 3, Brewing Lager Beer

So, you have your lager fridge all set up and ready to go, and you’re ready to brew that epic Doppelbock you’ve always dreamed of. What do you need to do?

Well, the good news is that producing your wort is done exactly as it would be if you were making an ale. If you’re extract brewing, you’ll start with steeping grains, you’ll stir in your extract, you’ll boil your hops, and you’ll chill the wort you’ve produced.

Handling Lager Yeast

Now things get a bit different, because lager yeast doesn’t work like ale yeast. As we discussed before, lager yeast works at much colder temperatures than ale yeast. That means it is also less comfortable with high temperatures. While you can get away with adding yeast to 82 or 84 F wort with at least some ale yeasts, that temperature can kill lager yeast. You need to get your wort temperature below 80. I live in Florida, so my tap water isn’t really cold, but I can consistently chill to 78 with an immersion chiller, and I’ve never hurt my yeast at that temperature.

The colder temperatures at which lager yeast thrive also have the effect of slowing the yeast’s metabolism down pretty significantly. If you’re used to making ales, you’re probably comfortable adding a packet of dry yeast or a vial of liquid yeast and not worrying much. Doing that with a lager yeast tends to lead to fermentations that never really start, and therefore, no beer.

There are three possible solutions to this. The most commonly suggested option is the worst one. Many first-time lager brewers are advised to leave their fermenter at room temperature until fermentation is going along well, then move the fermenter to the lager fridge. Do not do this. DO NOT DO THIS. Your beer ferments fastest in the first two days of fermentation, then gradually slows down. If you leave the beer at room temperature until it’s fermenting well, then begin chilling it, your fermentation may be half over before it’s reached the temperature it’s supposed to be fermenting at. That’s going to produce a lot of fruity esters, and possible nasty compounds from temperature-stressed yeast, and your lager is going to taste like an ale. Possibly like a crappy ale.

What you need to do is pitch much more yeast than are found in one packet or one vial, and begin chilling the beer immediately. This brings us to option number 2—you can buy 3 to 4 packets of yeast and add them all to the wort. This way you have the extra yeast you need to get fermentation going right away at the correct temperature. The obvious disadvantage is that all that yeast is expensive; you could easily add $25 to the price of your batch this way.

Option 3, which is the option I use, is to breed your yeast. I buy a single vial of liquid yeast (though dry works well too, I just don’t use it.) I have a small fermenter I use to make a little batch of beer, which makes the yeast multiply significantly. Then, when I want to make my lager, I have all the yeast I need at the cost of one vial of yeast and about $3 worth of malt extract. The disadvantage to this is that I have to think ahead, because I need to begin breeding yeast a week before brewing beer. I recommend this option strongly, and I am dedicating Friday’s Lager Week post to explaining in detail how to use a yeast breeder.

Primary Fermentation

Ok, so you have wort under 80 degrees in your primary, and using option 2 or 3, you’ve added a whole bunch of yeast. Next, you seal up your primary fermenter, you put it in your lagering fridge, and you set the temperature to a value that is appropriate to your yeast. The ideal temperature is given on the yeast label. If you’ve already thrown that away, you can check the manufacturer’s website. Most lager yeasts work best at 51-52 degrees. I really like White Labs’ Oktoberfest, which prefers about 55, and there are others that are a little abnormal, so just check. Within about 24 hours, you should have a vigorous fermentation at the correct temperature.

Yeast generate heat when they are eating and reproducing, and it’s not unusual for your beer to warm up 2-3 degrees at the most vigorous stage of fermentation. You’ll lose that extra warming as fermentation slows down. You should check your beer morning and evening while it is in primary fermentation to make sure the temperature is correct, and adjust your temperature controller accordingly. I normally have to turn mine down two degrees somewhere around day 3 or 4 to keep everything at a consistent 55 F.

Secondary Fermentation

Lager fermentation is slower than ale fermentation, but you’ll still be all right moving to a secondary after a week. I do this all the time, for the simple fact that Saturday is the day I have available for beermaking. Move your beer to your secondary, as normal, and return it to the lager fridge. Keep your temperature consistent with your primary fermentation (55 for Oktoberfest yeast, 52 for most others).

You’re going to want to keep the lager in secondary longer because of the slower fermentation. While ales can do 10 days-2 weeks in secondary with a good fast yeast, you’re going to want to keep your lager in secondary at least 3 weeks. Even then, you may have a few residual sugars that will still ferment. I typically keep sweeter styles, like Oktoberfest or Doppelbock, in secondary for 3 weeks, and drier styles for 4 weeks.

Diacetyl testing

When you think secondary is complete, you need to check your lager for diacetyl. Diacetyl is the compound used to produce artificial butter flavor in popcorn, and it tastes awful in beer. Lager is particularly susceptible to diacetyl buildup. I’m going to go into detail on dealing with diacetyl tomorrow, but for now, let me assure you that it’s easy to deal with, and there’s a good chance you won’t have any anyway.

Lagering

After the secondary is complete, and the beer is diacetyl-free, you begin the cold storage, or lagering, that gives lagers their crisp taste. There’s an old homebrewer’s rule of thumb that you should lager 10 degrees F cooler than you ferment. I’ve tried that, and the results sucked.

I prefer to crash cool my lager. I’ll take it down to 31 F, which is as cold as my fridge will go. It won’t freeze because of all the alcohol in the beer. I find that colder lagering gives me a crisper flavor, and it’s certainly faster. I lager at 31 F for 4 weeks, and honestly, that’s probably longer than is necessary.

Bottling

The lagering process is going to kill a lot of your yeast, so you’ll have to repitch. I have heard that many people use ale yeast when bottling their lager beer. I’m fanatical about keeping esters out of my lagers, so I’ve never tried that. I repitch the same yeast I used to make the beer in the first place, though I don’t bother with a starter this time. After bottling, I return the beer to the lagering fridge, back to fermentation temperature (52 or 55, usually), and leave them there for a week. When it’s done, you have a delicious lager beer!

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Lager week Part 2: Equipment for Lager making

As I mentioned yesterday, most of making lager is just like making ale. Up until you add the yeast, you follow exactly the same steps, so you don’t need any new brewing equipment. Lagers work perfectly well from extract, so they’re accessible to fairly new brewers.

However, once the yeast is in the beer, you treat lagers very differently from ales. Ales are super simple—pitch the yeast and put them in the corner of the room and let them do their thing. Lagers MUST be fermented cold. A good lager is crisp, clean and smooth. If your yeast is producing esters, you’re not going to get that crisp flavor, and yeast produce lots of esters at high temperature. If you don’t have a way of fermenting your lager at about 50 – 55 degrees, you’re not going to get a lager at all.

I have been asked, “What happens if I use lager yeast at ale temperature?” The answer is “nothing good.” It’s going to produce lots of esters, so you’re not going to get a good lager flavor, and the yeast is going to be stressed, so it’s going to make all kinds of nasty flavors from unhappy yeast.

Bottom line, if you want to make lager, temperature control is not optional. The normal way of doing this is with an old refrigerator or chest freezer. Either will work. Fridges are designed to operate at about 38 F, and none of them are going to give you temperatures in the low 50’s, where lager fermentation is done. You’re also going to need a temperature control override, like this one. You can set the temperature control to whatever value you like, and then turn the fridge down to its coldest setting. When the temperature in the fridge drops below the temperature you set on the controller, the controller cuts the power, preventing any further cooling. When the fridge warms back up, the controller will restore power.

These systems are ultrasimple to set up. The real barrier to lager making is the cost. A used fridge large enough to hold a fermenter is $100 or more, and the thermal controller is an added expense. My beer fridge is the most expensive piece of equipment I own, even more than my 10-gallon pot. (And we won’t discuss how my wife feels about my desire to buy a 2-carboy chest freezer to use as cold storage for lagers so that I can use the fridge I already have as a full-time fermentation chamber.)

(Actually, my wife is totally awesome about my brewing, and her objection to the chest freezer is a very reasonable argument that we don’t have the space.)

You also want to invest in some adhesive temperature strips because temperature control is so important.

Once you have all your equipment installed, there’s one more step that you need to do before you start that first lager. You need to calibrate your temperature controller. They’re very good, but I have yet to see one that actually gave you the marked temperature. Mine is off by 4 degrees across the entire range. If you want 55 F, you have to set it to 51. You also want to calibrate to the temperature of a liquid stored in the fridge, not to the air temperature of the fridge. Water changes temperature very slowly, so the air temperature is actually not telling you much. Slap a temperature strip on a carboy and fill it with 5 gallons of cool water. Set your temperature controller to 55 and stick the carboy in there. Give it time (24-36 hours) to cool, and check the strip. Adjust the thermocontroller up or down to adjust the liquid temp to 55. Once you’ve got it, WRITE IT DOWN.

Now, you’re ready to brew some lager! And tomorrow, we’ll talk about how.

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Lager Week, Part 1: Lagers and Ales

Welcome to Lager Week!

This week, we’re going to do a series of posts on making homebrew lager. If you love pilsner, Dopplebock, Oktoberfest, Munich Helles, or Rauchbier this week is all about you!

Lager-making not significantly different than making ale, though it does require some special equipment and procedures. It is accessible to any homebrewer, from the newbie with one batch of extract under their belt to the most hardcore all-grain Hausbräumeister.

Lagers and ales are the two most important categories of beer, comprising virtually all of the world’s commercial beer production. Preferences are highly regional, with lagers dominating in most of Europe, and in American macrobreweries, and ales dominating in Britain and in American craft breweries. (The fact that well-made American beer is mostly ale, while American garbage is mostly lager should not be taken as evidence that lagers are lousy. We just don’t make many good ones in the US.)

So, what’s the difference? The biggest is temperature—ales are fermented at 62 F or warmer, lagers are fermented at 56 F or below. (There are a few styles in that gap that kind of blur the lines. The German Kölsch is a noteworthy example.) Many references refer to “top-fermenting” and “bottom-fermenting” yeast, which I avoid. Where the inactive yeast congregates is basically due to the temperature, and the fermentation actually occurs throughout the liquid portion of beer.

So, cold-fermented beer is lager. Warm-fermented beer is ale.

There’s more to it than that, of course. Ales are faster to make, and require less equipment. This is why ales outnumber lagers in homebrew and craftbrew circles by a mile. Lagers almost always go through a cold-storage stage to condition them. Ales don’t. So, a homebrewer with an artificial carbonation system can turn around an ale in 2 weeks, and with natural carbonation, ales are ready in 3-4 weeks. Even with sophisticated equipment, it’s difficult to get a lager from brew day to drinking in less than 6 or 7 weeks. It’s that storage that gives lager their name. Lager is the German word for a storage facility, and lager beer has its origins in the German-speaking world, especially in Bohemia, Bavaria and Austria.

There are significant flavor differences. A good lager is crisp. A good ale is complex. Comparatively, there are more flavors bouncing around in an ale than there are in a lager. This has everything to do with yeast biology. Most of those flavors are tasty chemical compounds called “esters,” and yeast are much more efficient at making esters at higher temperatures, so you get a lot more in ales. In an extreme case, they can make the beer taste almost fruity

The difference in flavors has a significant impact in how you design a good lager or ale. Of course, you want both to be balanced, but lagers are more sensitive to subtle changes, whereas adjusting an ale’s flavor can take pretty big changes. I think of lager making like trying to balance mice on a see-saw, and ale-making like trying to balance buffalo. The goal is the same, but you have to approach it differently.

Tomorrow, we’ll discuss the special equipment required for lager-making. Wednesday, we’ll look at brewing and conditioning a lager, Thursday, we’ll talk about handling lager yeast, Friday is all about diacetyl and Saturday, we’ll talk lager recipes.

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Brown bottles? Green? What color bottles should you use for homebrew?!

If you’re like me, and you primarily use beer bottles that are leftover from commercial beers you’ve bought, you have a mishmash of different sizes, shapes and colors. You may be wondering if some of those bottles are better to use than others. Almost every homebrew site recommends brown bottles. Sam Adams made an advertising campaign about how only brown bottles protect beer from the light. But plenty of companies use green or clear bottles. What’s going on?!

First off, it is very true that light can damage beer. Specifically, it makes beer go skunky. You may be aware that the primary bittering chemicals in hops are the alpha-acids. One subset of those are the isohumulones, or iso-alpha acids. Under normal conditions, isohumulones are stable, but if you do some funky chemistry to them, they react with amino acids. Some of those amino acids have sulfur in them, and when chemically altered isohumulones react with them, they produce chemicals that have the odor and flavor of skunk spray. Clearly, this is not good.

To produce skunky flavors from your isohumulones, you need two other components. One is riboflavin, which comes from your malt. (Riboflavin is Vitamin B2—beer is nutritious!) The other is ultraviolet light. UV provides the energy to alter the isohumulones, and riboflavin catalyzes the reaction producing the skunkiness. As a homebrewer, you can’t avoid having isohumulones and riboflavin in your beer, so you need to protect it from UV. Because this reaction requires light, beer that has been affected is called “lightstruck.”

Brown bottles are by far the best for filtering out UV. Contrary to popular myth, glass is a mediocre UV blocker at best. Yes, your car windshield is 95% UV proof, but that’s from the high-tech coatings, not the glass. The iron that is used to make brown glass is a good UV blocker, so brown bottles are relatively safe to use. In the real-world tests I have seen, green glass has performed about halfway between clear and brown glass, and the lightproofing of clear glass is poor.

So, you should use brown bottles if your beer is going to be exposed to any significant amount of light. If you store your beer in the dark until right before you drink it, it really makes no difference at all. Bear in mind, though, that clear bottles can go skunky in about an hour in direct sunlight, which may matter if you’re taking your beer to a tailgate and putting it in an open ice bucket.

Not all beers get lightstruck at the same rate. The more IBU’s you have, the faster the beer will go skunky. More hops means more isohumulones, more isohumulones means more molecules that can make nasty sulfur compounds. Dark beers will go skunky faster than light beers simply because dark beers absorb more light. That means they’re taking in more UV, thus altering the isohumulones more quickly. This is why light, low-hop lagers are the beers typically found in green glass.

So what’s up with the clear glass bottles? Newcastle Brown Ale comes in one, and it’s dark. Why doesn’t it have a major problem with being lightstruck? If you’re a large-scale commercial brewer, you’re almost certainly not using actual hops in your brewing. They use hop extract instead. (This is why so many breeds of high-alpha hops have been produced in the last 40 years—you get more hop extract per acre. It’s nothing to do with flavor at all.) You can chemically modify the hop extract to remove the isohumulones. If you don’t have isohumulones, your beer cannot get lightstruck. It’s not cheap, but if you’re doing it to large batches of hop extract, it’s actually not too bad. For many macrobreweries, the added cost is less than a penny per bottle and is a worthwhile investment in protecting the product.

For the homebrewer, though, the best bet is to stick to brown glass, or to keep your bottles in the dark until right before drinking them.

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Beginners’ Tuesday—I have my starter set. What should I buy next?

A wort chiller, no question.

Most beginning homebrewers chill their boiled wort to a temperature cool enough to add yeast (the pitching temperature) by putting it on an ice bath in their sink. This works, but it’s slow. I remember it taking about an hour or more to bring my wort down to 75 degrees. I got a very simple wort chiller for Christmas a few years ago, and now it takes less than ten minutes.

Simple wort chillers are coiled lengths of copper tube that you clean, sanitize, and plunk right down into the hot wort. There’s a fitting on one end that fits onto an outdoor spigot. Fittings for kitchen sinks are also available. The other end is simply a drain. You run cold water through the chiller while it’s sitting in your hot wort, and the wort gets cool very quickly.

Wort chillers are awesome for two reasons. First, the cooling stage is when your beer is most susceptible to infection. Any bacteria that get in before boiling are killed by the boil, but any that find their way into the cooling wort will make it into your beer. So, the faster your cooling phase, the less time malevolent bacteria have to get in.

Second, a wort chiller pays for itself. How much do you spend on ice for an ice bath? Ten bucks? Fifteen? A simple immersion chiller costs fifty or less. In five batches, you’ve broken even, and the chiller will last forever.

These wort chillers are effective even for five-gallon all-grain batches. You can move up to more efficient (and more expensive) counterflow chillers, but they are thoroughly unnecessary unless you want to move into larger batches.

I can’t recommend adding a wort chiller to your kit highly enough. You can find lots of options at amazon, as well as at your local home brew store.

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