Oxidation is a chemical reaction that occurs when a substance reacts with oxygen. It is a process where atoms or molecules lose electrons to oxygen or other oxidizing agents. This reaction can alter the chemical composition and properties of the substance. It is important to avoid oxygen exposure during beer fermentation. When oxygen comes in contact with fermenting or fermented beer it can cause several negative effects including negative impacts on the quality and flavor of the beer. Here are a few reasons why oxygen should be minimized during fermentation:
1. Off-flavors: Oxygen can react with the compounds in beer, leading to the development of off-flavors. This is particularly true during fermentation when the yeast is actively converting sugars into alcohol. Oxidation reactions can produce undesirable flavors such as cardboard, stale or sherry-like notes, and a loss of freshness.
2. Stalled fermentation: Oxygen exposure can potentially disrupt the fermentation process and lead to a stalled or incomplete fermentation. Yeast requires an oxygen-free environment to perform its job effectively. Oxygen can inhibit yeast activity and growth, leading to sluggish or stuck fermentation where the yeast is unable to fully convert sugars into alcohol.
3. Spoilage: Oxygen can also contribute to the growth of spoilage microorganisms. While yeast is a desirable microorganism in beer fermentation, other bacteria and wild yeast strains can thrive in the presence of oxygen. These unwanted microorganisms can produce off-flavors and spoil the beer, resulting in an unpleasant taste and potential health risks.
To prevent oxygen exposure during fermentation it is suggested that a brewers take precautions. The use of a sealed fermentation vessels, such as fermenters with airlocks or conical tanks with controlled gas exchange is your budget allows for it . It is also suggested that you purge your keg with carbon dioxide or nitrogen to create a protective atmosphere for your beer. Additionally, careful transfer and handling techniques are employed to minimize the introduction of oxygen during and after the fermentation process.
By avoiding oxygen exposure during fermentation, brewers can maintain the desired flavors, aromas, and quality of the beer. The above photo is the system that I use. After I transfer the wort from the brew kettle and pitch the yeast in the conical fermenter, the only time that the fermenting beer has the opportunity to come into contact with oxygen is when I add dry hops. I try to do this while fermentation is still occurring so that there is a layer of krausen containing CO2 filled bubbles to purge any oxygen that may have entered the fermenter while the lid was briefly off. I use CO2 to transfer the finished beer into a keg that has been purged with the CO2 that was created during fermentation.
Recently one of the things I have been focusing on with my beer making is fermentation practices. For a while now I have been using a temperature controlled fermentation chamber and yeast starters to make sure that I had sufficient quantities of yeast and an ideal environment for the yeast to ferment in. That being said, I have been pretty relaxed when it comes to oxygen levels and have been working on making progress in that area.
Just some basic information on oxygen and home beer brewing. At certain points in the beer brewing / beer fermentation process, oxygen can be either your best friend or your worst enemy and it is important to know when to add and when to avoid it. Thankfully it is pretty easy to keep track of! The only time that you want to introduce oxygen to your beer is post boil and once the wort has cooled down and you are preparing to pitch your yeast. The reason for this is that yeast requires oxygen for healthy propagation. “Yeast use oxygen for cell membrane synthesis. Without oxygen, cell growth will be extremely limited. Yeast can only produce sterols and certain unsaturated fatty acids necessary for cell growth in the presence of oxygen. Inadequate oxygenation will lead to inadequate yeast growth. Inadequate yeast growth can cause poor attenuation, inconsistent or long fermentations, production of undesirable flavor and aroma compounds, and produces yeast that are not fit for harvesting and re-pitching.” – Wyeast Labs. During the boil process, much of the oxygen is stripped away from the wort, so it is good practice to reintroduce oxygen back into the wort. There are several ways to accomplish this but the key is to do it in a sanitary way. Many brewers will rapidly stir the wort or swish it around in the fermenter and others will pump pure oxygen into the fermenter with a diffuser stone. In my setup I keep the yeast oxygenation / aeration process pretty simple and meet in the middle. I use an aquarium pump with a stainless steel diffuser for about 15 minutes once I have transferred my wort to the fermenter. It has an inline HEPA filter to make sure I am not blowing a bunch of dust or wild yeast into my wort. I also pitch the yeast at the same time. You can pickup at yeast aeration kit from MoreBeer.com for about $35.
Once you have aerated your wort and begun the fermentation process you will want to do everything you can to avoid introducing oxygen into your beer. Thankfully, the yeast will help you with this process. As the yeast consumes the oxygen to replicate itself and converts the sugar in your beer, it is creating two main byproducts which are alcohol and CO2. The creation of the CO2 will help purge any residual oxygen from the fermenter. The next step is doing your best to avoid introducing oxygen to your beer when it comes time to transfer your beer to the keg. The most common way to do so is to purge your keg with CO2 from a CO2 tank and then push your beer from the fermenter with CO2 from a CO2 tank. In my setup the only thing that I do differently is that I use the CO2 being expelled from my fermenter during active fermentation to purge my keg. You can view the setup in the photo at the top of this article to get a visual, but basically I am diverting the CO2 to the keg as opposed to pushing it the a flask filled with sanitizer. I user mini stainless steel ball lock valves that I picked up here from Amazon. For the final step, I push CO2 into my fermenter to build about 3 PSI of pressure and move the fermented beer from the fermenter to the keg as shown in the following image.
Perhaps the biggest brewing trend of 2019 has been the explosion in popularity of Kveik (pronounced Ki-Vike) yeast. Kveik is a group of Norwegian yeast strains that were previously best known for their use in Norwegian farmhouse brewing. Kviek yeast has been used in brewing for over 400 years now, but recently has seen a resurgence in popularity because of some of its unique properties.
So what is so special about Kviek? Primarily it boils down to temperature! Unlike typical ale yeast, which ferments best around 68F, Kviek yeast strains ferment well up to temperatures of 100°F (a temperature that would kill most lager or ale yeast strains). In fact, the sweet spot for Kviek yeast strains is between 70°F and 95°F and at high temperatures it imparts little noticeable difference in ester production. The ideal fermentation temperature for a lager is typically between 45F and 60F ; for an ale it is 68F and 72F. Unlike Kviek, most lager and ale yeast strains produce undesirable off flavors / esters once they exceed their optimal fermentation temperature ranges. If a home brewer does not have the ability to control their fermentation temperature this often times translates to sub par beer.
The high fermentation temperature range of Kviek yeasts has another big benefit, SPEED! You know how cold blooded animals like snakes and lizards move slower when it is cold outside and faster when it is hot? Well yeast works the same way. When the temperature is high, yeast gets super charged. It is the reason why lagers ferment so much slower than ales. Using Kviek yeast is kinda like trading in your old 2007 Dodge Caravan for a 2020 Porsche GT2 with a carbon fiber spoiler, reduced weight seats and upgraded suspension package.
Not wanting to drive a Minivan any longer, I figured I would give Kviek a shot and see what all the hype was about.
Home Brewing with Kviek Yeast
To take full advantage of the Kviek fermentation benefits, I purchased a dual stage temperature controller and an “always on” heating pad for my fermentation chamber (converted chest freezer). Keep in mind that as yeast ferments it is releasing a bunch of energy as it replicates, digests sugar, pees out alcohol and burps out CO2. In the image at the top of this article, you can see that I set my fermentation temp to 86F and the yeast brought the temperature all the way up to 90.1F during primary fermentation. It is advised that you make sure you keep that in mind as you set your desired fermentation temperature into your temp controller if you happen to use one.
For my first Kviek batch, I fermented a Double IPA and used the Imperial Loki Kviek yeast strain. Here is some of Imperials information on it:
Imperial Loki Kviek Yeast
TEMP: 65–100F (18–38C) FLOCCULATION: MEDIUM-HIGH ATTENUATION: 75–85% ALCOHOL TOLERANCE: 10%
Norwegian Voss Kveik Strain that can be used in a wide variety of beer styles. A traditional Norwegian Kveik strain that has an extremely wide fermentation temperature range. This strain has been traditionally used in Norwegian farmhouse style beers however, due to it’s fermentation temp range can be used in a variety of beers from pseudo lagers, Belgian inspired, and hop forward beers. The possibilities seem endless when fermenting with Loki. On the cool end of the range Loki is super clean; producing little to no esters. On the high end of the fermentation range, 85-95F, it tends to produce a huge fruit ester profile.
I created a yeast starter with the Kviek yeast the night before. The brew day went well with no mishaps. I pitched the wort, placed the fermenter in the fermentation chamber and checked in on it periodically. The fermenter was already bubbling after just a few hours. I had never seen fermentation begin so rapidly. Primary fermentation concluded in just 3 days which was incredibly fast for a beer with an approximate ABV of 8.5%. I dry hopped the beer for 3 additional days and then cold crashed for 2 days at 45F. My highest fermentation temperature reached was 91F.
Battle Hammer – Viking IPA with Kviek Yeast
I named my first Kviek beer Battle Hammer – Viking Double IPA. It is extremely hoppy, but with a name like Battle Hammer, I figured it needed to be. I had only let the beer condition in the keg for about a week and at this point it is still a little cloudy; I am hoping it will clear a bit over the next couple of weeks. The beer tastes fantastic; very clean and with no off flavors that might have come from the yeast. I was unable to taste any noticeable difference between brewing with this Kviek Loki yeast to when I had brewed this same beer in the past with a Wyeast 1056 American Ale yeast strain. The beer came out great, my only change would be to perhaps swap out some of my old school hops for some Citra to brighten the hop profile a bit.
To celebrate the beer, I had created a tap handle inspired by it’s Norwegian heritage.
Norwegian IPA – Battle Hammer – Kviek Yeast – Tap Handle Being Welded
The runes on the tap handle read “IPA” or at least that is what the Google tells me.
I already have another Kviek fermented beer in the works. For this batch I am using the Omega Kviek Hornidal strain. It is going to be a Coconut Milkshake Hazy IPA. I am hoping that some of the tropical not from them Hornindal Kviek strain take hold in the beer. The hop profile of this beer is far more subtle than my Battle Hammer Viking IPA, so the yeast should have a greater impact on the flavor of this beer. Here is some information on the Kviek yeast stains put out by Omega.
HotHead is Norwegian in origin from the Stranda Kveik. The famous Lars of Larsblog collected it in Norway and then sent it away for isolation. This isolate has a uniquely pleasant fruitiness and an absurdly wide fermentation range, and ferments clean across the entire range. This is great for brewers who want to be energy efficient with temperature control, or who lack temp control in warm climates. It maintains a stable ester profile, and we advocate it’s be used for hoppy American ales.
Voss Kveik is also a Norwegian farmhouse strain from the Gjernes farmhouse which is new to US brewers. It maintains character over a broad temperature range with subtle orange citrus notes that match fruity hops well.
Attributes: Medium Flocculation, 75-82% Attenuation, 62-98° F Temp Range, 12% ABV Alcohol Tolerance
A wonderfully unique Norwegian farmstead Kveik. Hornindal presents a tropical flavor and aroma of fresh pineapple, mango and tangerine, which complement fruit-forward hops. Add even more dimension to C hops with a high fermentation temperature, intensifying aroma and fermentation speed. Ferments well at 90+° F.
Attributes: High Flocculation, 75-82% Attenuation, 72-98° F Temp Range, 16% ABV Alcohol Tolerance
Beer Bug Home Brewing Internet Based Monitoring System
Limited time and quantity promo code from MoreBeer.com – MoreBeer
Promo Codes for the Month of September 2016 Coupon Code Date: 9/5/2016 Promotion Details: Save $40 on a Digital Homebrew Monitor was $199 Promo Code: BEERDEAL Coupon Code Description: MoreBeer currently has a coupon code that will save you $40 on a Digital Homebrew Monitor! The Beer Bug is a fantastic piece of homebrewing equipment that measures the actual specific gravity, ABV and even temperature of your fermenting homebrew beer every minute. It then compiles the homebrew data and sends that information to your own free online account. It makes it super easy for you to log on at the TheBeerBug.com or via an internet based app on your phone to see exactly how your fermentation is doing from anywhere! In fact, this homebrewing technology has three graphs that are created for each of your beers to log how specific gravity, alcohol %, and temperature changed over the course of the fermentation. The Beer Bug gives you the knowledge to make better beer and saves you time!Understanding what happens during fermentation, and how to control it, is often what separates good brewers from great brewers. The Beer Bug is the tool that gives you the information you need to know things like if your fermentation temperature inside the chamber is too high or too low, when fermentation is nearing completion so that you can prepare to dry hop, keg or bottle and even what the lag time is on your beer is.
Here are the specs on the Beer Bug, digital home brewing monitor with web interface:
Fits just about any fermentation vessel
Actual gravity sensor hangs from your BeerBug into your beer and can be lengthened or shortened to accommodate any vessel
Sends information via your local WiFi network
Rechargeable battery in the homebrew monitor has a 25 day charge life
Free account on TheBeerBug.com
Easy to setup and configure
Android and iOS Apps available for your phone or tablet
Software upgrades will automatically be sent to your Beer Bug via WiFi as released
It has been about a year since I purchased my 7 Gallon SS BrewTech conical fermenter and 14 gallon stainless steel conical fermenter. I have been very please with their performance and am happy to report that I have not had a single issue with them. The quality of the manufacturing is top notch and they were the best priced stainless steel conicals that I could find. Best of all they even shipped them for free, saving me a bundle.
Their price was recently reduced and they also release an upgraded Brew Master version of their already quality built line of stainless steel conical fermenters. So if you are looking to upgrade your homebrewing fermenters, this may be a great time to do so.
These stainless steel conicals come loaded with features, here are some of the specs:
Certified Food Grade 304 Stainless Steel Construction
Patent Pending Stainless Steel Rotating Racking Arm
They have a full range of these stainless steel homebrewing fermenters, including 1/2 barrel and full 1 barrel sized fermenter. Their brew bucket line of stainless steel fermenters is also on sale right now starting at $195.
It seems like often times home brewers place a ton of attention of the brewing process and not enough on the fermentation process. The truth is that both are critical to making a good beer. Brewing yeast is highly temperamental and is heavily impacted by temperature. If the temperature is too cold it begins to shut down, slowing replication and fermentation. If this happen at the wrong time in the fermentation process you will wind up with a sweet and under fermented beer and potentially bottle bombs. If your temp gets too high high you may flash ferment your beer ending up with a bunch of off flavors created by your yeast. What you want in a nice consistent temperature, specific to your lager or all yeast strain. A temperature that is consistent 24 hours a day, not fluctuating wildly day and night. For most ale yeast strains you are looking for a target temp of about 68 F. Depending on where you live, what time of the year it is and what type of equipment you have available will determine how you want to handle controlling your fermentation temperate. In any case, you are probably going to want to purchase a temperature controller such as the Ranco Digital Temperature Controller pictured above. I have used both Ranco and Johnson controllers and would recommend either; the Ranco just tends to be a little less expensive. In an ideal situation you would hook the temperature controller to a chest freezer or refrigerator to help insulate the beer from the elements.
If you are looking for a digital temperature controller for your home brewing fermentation, MoreBeer currently has the Ranco on sale for $83.95 and is Available Here
Recently I decided that I would create a temperature controlled RIMS systems for my home brewery. I picked up a Ranco Digital Temperature Controller (model # ETC-111000-000) to manage the temperature regulation. I have not quite completed the entire Recirculating Infusion Mash System, but I just wrapped up the Ranco wiring and thought that I would share what I learned in case it will help out anyone else.
The RIMS heating element that I am using is a stainless steel 120v heating bar, so I have configured the Ranco for 120, but the Ranco thermostat is also capable of handling 240v; it just requires a slight wiring modification. I would like to point out that I am not a professional electrician. Electricity can be extremely dangerous to work with and may result in death. You should always consult with a professional electrician when attempting a project such as this. Manufacturer hardware designs sometimes change and you should refer to your instructions prior to beginning. Here is a wiring diagram that I used for my Ranco Temperature Controller.
Ranco Digital Temperature Controller Wiring Diagram
I cut apart a heavy gauge extension cord to use for my wall power connection and for the wiring I used to connect to my output plug. Inside the extension cord is a ground wire, common wire and hot wire. In the diagram above I use the green wire to represent ground, the white wire to represent common and the dark red wire to represent hot. Please be aware that different cables use different colored wire to represent different things, these colors are just meant to be an example. I ran the grounding cable from my extension cord directly to my output plug ground connection and also grounded it to the metal case that I am using to house my Ranco temperature controller, plug and switches. I spliced the white common cable from the extension cord and connected it to the “COM” port on my Ranco and ran an extension wire to the common connection point on my output plug. Since the RIMS heating element that I am using is 120v, I ran the hot wire from my extension cord to the Ranco “120” port. I then connected a small length of heavy gauge wire from the “120” port on the Ranco to the “C” port on the Ranco Temperature Controller. Lastly, I ran a segment of red wire from the Ranco “NO” port to the hot wire connection on my output plug. I reviewed my work to make sure that all of the wires were connected properly and there was no bare wire exposed. I then connected the device to a GFCI outlet and tested the device with a voltage meter to make sure that everything was working as intended. The Ranco is great because you can select whether you want the power to activate when the temperature drops below a certain point or rises above a certain point which means that it can be used for either a RIMS type device or to control the fermentation temperature in a freezer or refrigerator without having to rewire the device or modify the hardware.
Ranco 120v Thermostat
If you are not comfortable doing electrical work or if you would prefer to avoid the hassle, you can purchase a wired Ranco Digital Temperature controller. You can find several different options available here at a great price via the link below. They also have spare temperature probes and mounting brackets for the Ranco available if needed.
While cleaning out your fermenter have you ever wondered if you could reuse the yeast that has collected on the bottom? The answer is yes, you certainly can! You can actually often reuses your yeast 4 or 5 times with out the likelihood of having any ill effects from mutations or high quantities of alternate yeast strains impacting the flavor of your beer. Yeast isn’t cheap at around $7-$10 for a vial of the good stuff, so you might as well get your moneys worth!
Here are some basic things to consider when reusing your home brewing yeast.
It is best to reuse the yeast as soon as possible. You will probably want to consider discarding it after approximately 6 months. If you are pitching the yeast more than 30 days after harvesting it from your fermenter, I would recommend creating a starter with it to help insure viability.
Only reuse your yeast 4-5 times. Each time you reuse the yeast, mutations will occur and the probability of alternate yeast strains impacting the flavor of your beer will increase.
Do not reuse the yeast if the ABV of the beer that you harvested it from exceeds 6.5%. High alcohol levels weaken and destroy your yeast.
Do not reuse yeast from a heavily hopped beer. Like with alcohol, an over abundance of hops (from a dry hopped IPA for instance) will diminish the longevity and potency of your yeast.
Do your best to avoid harvesting the trub along with your yeast. This is most easy accomplished via a conical fermenter. It is also possible transfer the yeast slurry and then rinse and decant your yeast with sanitized water to separate it from the trub.
Harvesting Beer Yeast
Yeast should be stored at approximately 36 F in a sanitized vessel. Keep in mind that even at that temperature the yeast may still be active and can create CO2. So beware as your container may explode if too much fermentable sugar remained behind in your harvested yeast solution and the vessel is unable to vent the pressure.
If you are interested in purchasing a conical fermenter or yeast harvesting cylinder; many options can be found here:
Sometimes how brewers take for granted how big of an impact yeast makes on a beer. It seems like the grain bill and the hops garnish the lion share of attention, but the truth is that the yeast can play just as large of a role in certain beers. This is especially true with sours, lambics, gueuze and wild ales. One of the main yeast stains commonly used with wild ales and sours is brettanomyces or also commonly called brett.
Brettanomyces is very special because in addition to converting sugars to alcohol and CO2, it also creates a high amount of acetic acid and off flavors in certain environments. Brett or Brettanomyces is often described as adding a funky or horse blanket like flavor to beer and as you can imagine, in most cases is undesirable. It is important to note that if you are going to dabble in the use of brettanomyces or other souring bacteria such as lactobacillus and pediococcus you will want to consider setting aside specific equipment such as fermenters, kegs and racking canes for your wild ales and sours. Once these yeasts and bacteria come in contact with your fermenting equipment they can be more difficult to eradicate than typical brewing yeast strains due to their ability to survive in high temperatures, tolerate high alcohol levels and their ability to survive in low pH environments. If not, it is very important to make sure that you practice proper cleaning and sanitization methods to insure you will not contaminate future batches of beer.
Recently Brettanomyces has made become very popular in alternative beer styles. It is a powerful tool to have for a creative brewer who is working on designing interesting and flavorful beers. It is also an important reminder of just how important both yeast and fermentation conditions are in creation of a beers taste.
If you are looking to taste examples of well crafted brettanomyces beers, I highly recommend Russian River Sanctification which is a 100% brett beer and also any one of the Crooked Stave 100% brett release beers.
Wort is the name given to the sugar rich liquid that is extracted from the mash prior to fermentation. Prior to the boil, when the hops have not yet bittered the wort, it is known as sweet wort. After the boil but prior to fermentation, it is known as bitter wort since the beta acids from the hops have imparted a bitter flavor upon it.
A photo of sweet wort being transferred from the mash tun to the boil kettle after sparging had completed:
Wort (unfermented beer) being transferred after sparging.
Beer sediment is the collection of solids that fall out suspension of a fermenting or conditioning beer. Sediment is mostly comprised of yeast, grain solids, hop solids, and adjunct solids. As the beer ferments or conditions, the dense solids fall and settle to the floor of a fermenter, conditioning vessel, or bottle, in the case of a bottle conditioned beer. The sediment is typically discarded, but if the yeast is still healthy, it may be recycled from the sediment to be used to ferment future beers.
Secondary fermentation is the process of transferring your beer to a secondary fermentation vessel to allow the beer to complete its fermentation cycle and condition in a clean environment. The primary reason for a secondary fermentation is to improve the taste of a beer. Towards the end of the primary fermentation, much of the yeast, beer solids, and hop solids will fall out of the beer and form sediment on the bottom of the fermenter. If left in contact with the beer too long, the dead yeast and solids can impart off or undesirable flavors upon the beer. For this reason, many brewers choose to rack the beer off of the sediment into a secondary fermenter to allow the beer to finish out fermentation, clarify, and condition.
The need for secondary fermentation is somewhat dependent on the style and characteristics of the beer that you are creating. For instance, if I am brewing an American wheat hefeweizen, I probably will not go through the trouble of a secondary fermentation because it is a relatively low alcohol beer with a low flocculating strain of yeast. This means it will ferment quickly, so the beer is only in contact with the sediment for a short period of time, and much of the yeast will remain in suspension with this style of beer, so a yeasty taste and cloudy appearance is appropriate.
If I was brewing an IPA with a high starting gravity, and I wanted to highlight the hoppy flavor of the beer, I would certainly conduct a secondary fermentation to remove as much yeast and yeast flavor from the finished beer to help both with taste and clarity. Depending on the beer style, gravity, fermentation temperatures, yeast strain, and yeast health, a secondary fermentation can typically last anywhere from two weeks to several months. When conducting a secondary fermentation on certain beers, such as sours, the secondary fermentation can in some cases last over a year.
An imperial chocolate stout being racked into a secondary fermentation carboy,