By Anthony St. Clair
For the Oregon Beer Growler
Wrangling yeast can be as easy as moving it from one fermenter to another. Unless you have four yeast strains in regular use and a tight production schedule that can’t always wait for the yeast to be ready. That’s why, earlier this year, Eugene-based Ninkasi Brewing Company brought online a dedicated system of yeast propagation and storage tanks.
“Yeast is the only raw ingredient we supply ourselves,” says Dr. Daniel Sharp, director of brewing process development. “In addition to beer, we also make yeast, so having dedicated vessels for making and storing yeast is no-brainer, especially due to the amount of beer we make and how many yeast strains we use.”
Originally championed by Ninkasi’s in-house lab and quality control teams, the propagation system (“prop” for short) arrived earlier this year. “Before having this system, we were all doing this with our current brewing and tank setup, trying to fit it in and make it work,” says Sharp, “but that’s challenging when you have all your fermentation vessels full. But you need vessels to make yeast to make more beer. It was an easy ROI, and it makes yeast production easier for the whole team.”
The custom-made system was fabricated by W.M. Sprinkman, a dairy, food and beverage equipment manufacturer in Wisconsin. The system is comprised of three 10-barrel brinks and one 5-barrel brink for storage as well as 20- and 30-barrel props. Controls include gravity, gas composition (vessel atmosphere), agitators to aid cooling and homogeneity, and temperature. For oxygen, “we used to use a standard dosing rate, like most brewers, added at the beginning of fermentation,” says Sharp. “Now we can add oxygen based solely on how much the yeast needs to grow, instead of how much it needs to ferment. We’re still working with it to figure out the optimal amounts, but playing with the oxygen levels for the yeast is helping us grow healthy yeast faster.”
A positive displacement pump, great for moving thick liquids while being gentle on the yeasts, is used for transfers. After yeast is grown in the lab, it’s added to the prop and then pitched into wort during knockout. One 30-barrel batch of yeast can pitch a full 550-barrel fermenter. Instead of pitching by volume, the tanks are connected to load cells, so Ninkasi’s brewers know how much yeast is being pitched down to the pound. “We also don’t like to waste things, especially yeast,” says Sharp. “Nailing in exactly the amount we need when we need it, that’s the goal.”
Installed and tested during March and April, Ninkasi uses the system for the full yeast propagation process. The benefits have been immediate. Yeast propagation used to take 14–21 days. Now it can be done in 10–12 days.
“The shorter time helps us be flexible and work with the yeast while it’s in a happy state,” explains Sharp, “while also working with the other needs of the production schedule. We look out weeks in advance, and the shorter time is a big win.”
Parallel environments ensure optimal conditions for both beer and yeast. “Fermentations are great for making alcohol but aren’t good conditions for yeast growth,” says Sharp. “The conditions for growing yeast are bad for beer, such as needing oxygen. With the props we can grow a healthy supply of our own yeast without compromising beer flavor. Also, by controlling the conditions of our yeast growth and health, we can better control the subsequent fermentation profiles.”
Depending on the schedule, now yeast can be taken straight from one fermenter to another, or it can be stored in a brink and used for up to 10 fermentations. With four strains in regular use (Helles Lager, English Ale, Chico Ale and German Ale), plus a house yeast library for special projects, it’s also easier to maintain the “yeast pipeline” so that yeast is at an optimal state for pitching. For example, the English Ale strain — used in flagship beers such as Total Domination IPA — is a “juggernaut” that has adapted well to Ninkasi’s brewery and higher-IBU and ABV beers, while providing softer blending aromas and flavors.
“We don’t do delicate yeasts that need coddling,” says Sharp. “We need tough yeasts.”
On the flipside, for a beer such as Hop Cooler IPA, the Chico Ale accentuates individual characteristics, and the German Ale yeast used in Sleigh’r Dark Double Alt Ale is less flocculent, so some residual yeast remains for a thicker mouthfeel.
“We are a yeast farming facility that makes good beer,” says Sharp. “Our job is to make good yeast, or we can’t make good beer.”
By Chris Jennings
For the Oregon Beer Growler
There are many things that can go awry during the brewing process. Anything that happens before your wort hits the fermenter is fixable, for the most part. Unfortunately, there’s not a lot to be done to salvage your precious beer if you encounter issues during fermentation. There are, however, a few steps you can try along with tips to avoid future tragedy.
The most important step that should be taken before any kind of fermentation begins is cleaning. Everything that touches your wort post-boil, during fermentation and post-fermentation should be sanitized. Use a cleaning solution that won’t leave a residue but will adequately remove all debris from equipment. A variety of chemicals are available at your local homebrew shop. What works best for you might not be what someone else prefers. The same goes for sanitizer. Ask your homebrew shop attendant for advice. That being said, this isn’t the Dark Ages and there are much better reasonably-priced options on the market besides bleach. The cleaning agent and sanitizing solution should always be two separate chemicals. While most cleaning agents can also act as a sanitizer, it’s best to be overly cautions.
The next thing to address is the fermentation equipment. Whether you are using plastic buckets, glass carboys or stainless steel containers, be sure that all the parts and pieces fit well to create tight seals. The stopper the airlocks go in need to be the right size and make sure that there’s only one way for gas to leave the fermenter. This will allow you to see active fermentation and it reduces the chance that something will find its way into the batch. Remember, the airlock is the line of defense against the outside world.
Sometimes liquid in the airlock can get sucked into the fermenter. And if there is anything undesirable in that liquid — a dead bug, for instance — you might infect your batch with bacteria. To avoid this, use sanitizer or 100-proof alcohol on the airlock just in case anything does reach that device.
Now that the post-boil equipment is cleaned, sanitized and properly installed, the next step to ensuring proper fermentation is the yeast itself. Proper pitch rates and ensuring there is plenty of oxygen are just a few factors to consider. When building a recipe, be sure you have a high starting gravity and account for that with a little more yeast than normal. That way your fermentation won’t stall, which could result in a product that is under-attenuated and too sweet.
Yeast doesn’t like to be abused, and the easiest way to hurt your yeast is with large temperature swings. If you are using a liquid yeast, you want it to be as close in temperature as the wort you’re pitching it into. A large temperature gap can rupture the cell walls of the yeast. Don’t let the yeast get too warm, though. If fermentation is too hot, you could end up with an entirely different set of problems.
Yeast also have two stages of fermentation. The first is aerobic where they actually consume oxygen to multiply. The second is anaerobic when the yeast begin to consume sugar and create all of those wonderful byproducts. The best time to introduce oxygen to the wort is before the yeast is pitched and after the wort is cold. Introducing oxygen after the pitch might create off-flavors.
As homebrewers, we can only guide the yeast to help us create award-winning beer. Give those little guys a fighting chance to reduce chances things will go wrong.
Fizzy Yellow Protocol [AG]
Fizzy Yellow Protocol [Extract]
By Chris Jennings
For the Oregon Beer Growler
Pushing the limits and finding new ways to tackle big problems is what drives many a passionate homebrewer. In the Pacific Northwest, a lot of innovation also revolves around the hop. Brewing huge IPAs can test our equipment and general knowledge about yeast. For instance, once you have that 1.095 starting gravity, getting the yeast to perform can be a challenge. Knowing how to approach common problems when making double IPAs will help you avoid a bad final product and possibly even create a great one.
Brewing Big IPAs
There are a few things to remember when crafting your own version of these big brews. As the name implies, you want to double everything: hops, malts and even yeast. If you’ve never made this style, you can simply start by doubling all of the ingredients in your favorite Northwest IPA recipe. Make sure you have enough grain or malt extract to hit a starting gravity of at least 1.065. Any starting gravity above 1.085 is considered “out of style.” Feel free to experiment. The mash will require a bit more water than normal to ensure a good extraction, so get a boil kettle that’s large enough to handle the extra volume.
When using extract, don’t exceed approximately 10 pounds for a 5-gallon batch. Non-fermentable sugars in the extract will add too much sweetness to the finished product. To make up any extra gravity, there’s no harm in using a small amount of sugar. This technique can also be used if you don’t quite hit the numbers you’re going for when brewing all grain. Add the sugar during the last five minutes of the boil to avoid caramelizing and stir frequently so that it doesn’t sink to the bottom of the pot and scorch. Due to the extra volume, boil for 90 minutes. That also provides 30 more minutes for hop additions. When timing this out, remember that anything incorporated in the first 45 minutes will significantly increase the bitterness of the beer.
Finessing the Yeast
Come yeast-pitching time, be sure you’re using a strain that will be able to tolerate the higher alcohol content you’re shooting for. This information should be available at your local homebrew supply shop. Additionally, it’s advisable to use two packets of yeast. The average yeast pitch has about 100 billion cells. According to yeast companies, this is sufficient for a 5-gallon batch with a starting gravity of 1.050, however, anything below 1.060 should lead to good fermentation.
The biggest problem with brewing higher-gravity beers is the yeast not doing its job. Make sure you help create a wort that’s the perfect, cozy home for those little yeasties to thrive and get to work. After your boil is complete, chill it quickly by using an ice bath or a chiller to avoid the production of dimethyl sulfide (DMS), a common off-flavor that can resemble the taste of cooked vegetables. It’s also important to ensure the yeast is the same temperature as the wort. Too much of a difference will cause the yeast cells to rupture. Take your yeast out of the refrigerator and allow it to warm up to room temperature. Before pitching, introduce oxygen to the wort to help get the yeast started.
Shaking the fermenter is adequate, but if you’re feeling adventurous, you can purchase an oxygenation assembly system that injects oxygen into the wort as it travels into the fermenter. You’ll also need a bottle of oxygen, which can be found at some hardware stores. Take care to not go overboard when adding oxygen.
Even after giving the yeast a fighting chance, it won’t always perform. In the event of stuck fermentation, when the yeast has gone dormant, there are still a few options. Adding more yeast to the fermenter is the quickest and easiest fix. However, the best time to do this would be before the wort has fermented at all because a later introduction could create off-flavors. If fermentation has gotten underway and then come to a halt, transfer the beer from the primary fermenter to a secondary. This will rouse some of the yeast and get the beer away from the dead yeast and protein.
Don’t focus solely on the activity in the air lock because many things can make it bubble. The only way to know whether fermenting has stopped prematurely or finished the way you’d planned is by taking a gravity reading. Even if you didn’t hit the numbers you’d hoped, the test of the tongue is, perhaps, most important. Only you can decided if your method needs adjustment or if you’re on the way to brewing an award-winning double IPA.
Jake's Wedding Imperial IPA [AG]
Jake's Wedding Imperial IPA [Extract]
By Chris Jennings
For the Oregon Beer Growler
As homebrewers, it seems as though we face a nearly unlimited amount of choices for every detail in making beer: whole hop or pellet, all grain or extract, liquid malt extract or dry malt extract. The list goes on and on. For the most part, there are only subtle differences in the results with most of these factors. However, the decision to go with either liquid yeast or dry yeast can not only change the outcome of your brew; it also will affect the entire process.
Finding Substitute Yeast Strains
Whether you’re using a recipe you spotted online or discovered it in a dusty tome in the basement of a library, there’s a good chance either way that it calls for yeast. Most directions are also very specific about what brand and strain of yeast must be used as well. Deviating from the plan will not yield optimal results, according to the author of the recipe. But at times, there are some yeast varieties that simply aren’t available. Either the company has disappeared or the strain is a seasonal release, so finding a suitable substitute can be a challenge. Of course, every challenge is just an opportunity to discover something new and amazing.
There are some yeast strains that are so similar, either liquid or dry, you won’t notice any difference. Therefore, if your recipe calls for White Labs WLP001 California Ale Yeast and your go-to homebrew shop is out, you can try the dry Safale US-05 from Fermentis. But things get a little trickier when your desired strain is no longer in production or only available seasonally. The best thing to do in this situation is to research as much about the yeast as possible and then compare it to what’s available. That information will allow you to make an educated guess about what will serve as an adequate substitute. You could also just select a completely different strain all together and create a new tasty variation. When selecting a new strain, there will be more options from all of the liquid yeast companies. Though there are some crossovers, keep in mind that the liquid companies have unique strains that are hard to substitute.
The most obvious difference between liquid and dry yeast is that one is stored in a fridge and in a liquid state while the other is vacuum-sealed on a shelf. The liquid yeast is branded as “fresh” because it is raw and has a shelf life. The liquid yeast needs to be stored in a cold place to preserve that freshness. However, dry yeast has been freeze-dried and resembles baker’s yeast. It should be stored in a room with low humidity. While dry yeast will last much longer than liquid yeast, it also does have an expiration date.
There are advantages and disadvantages to both dry and liquid yeast. Storing dry yeast is much easier. But liquid offers more variety. At the end of the day, homebrewers have many options, which just makes your next beer-making adventure even more exciting.
Holly Day Ale [AG]
Holly Day Ale [Extract]
By Chris Jennings
For the Oregon Beer Growler
During our homebrewing adventures, we encounter a vast new vocabulary that can seem like a foreign language to the average person. Being a homebrewer, however, means that we have an entirely new range of terms at our disposal. Often, a process or reaction that would’ve taken 10 words to describe can be summed up much more succinctly once you’re familiar with the jargon. One example of a new term you’ve likely stumbled across is attenuation. This describes the percentage of sugar the yeast will consume. Every yeast strain is different and many factors can affect how well the yeast performs.
Temperature is always very important to pay attention to during fermentation. As with each brew, every yeast has an optimal temperature range. Most strains perform best somewhere in the range of 65-72 degrees. There are, of course, exceptions. Belgians typically are at the warmer end of the spectrum whereas lagers need to be kept colder.
Temperature control is probably the most difficult challenge for brewers of every level. You can purchase fancy equipment to help with that, but if you don’t have those kinds of resources simply start by taking the air temperature of the room you plan to use for fermentation. Yeast will produce heat when it ferments, so as long as the room is about 5 degrees cooler than your ideal fermentation temperature, you will be on the right track. Whatever strain you’re using, make sure you’ve researched what temperature will provide an environment allowing it to perform at its best.
It’s in the Strain
All yeast strains have a temperature preference, but they also can be picky about the pH of the brew along with potential alcohol content. Be sure to do your homework on the beer style you plan to make. That will point you in the direction of the yeast strain you’ll want to use. There’s no need to rush out and purchase a pH meter or test strips. Instead, remember that darker beers are more acidic, so you want a strain that fits better with your grain bill.
Another factor to consider is gravity. If your starting gravity is too high, the yeast will have a hard time getting to work. It also may not ferment all of the potential sugars. Once again, research the individual strain to make sure, for example, the imperial wit you’re trying to produce will actually ferment completely. Most every yeast strain will indicate what style of beer it fits with by its name alone. However, some types of yeast can perform outside of the normal style guidelines.
Experimentation can be an exciting way to find these anomalies, but thorough research will help ensure that your finished product turns into the tasty homebrew you were shooting for.
Ale Gating [AG]
Ale Gating [Extract]
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