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FAQ: FERMENTATION QUESTIONS
With regards to fermenters, which is better - to use a blow off or an airlock?

The question is whether it is better to ferment in a 6.5 gallon carboy or bucket where you have an airlock and there is no blow off versus fermenting in a 5 gallon carboy with a tube attached to the top of the carboy that goes into a jar of water that acts as a blowoff and airlock. With the blow off method most of the krausen gets blown out the top. With the non-blow off method the krausen settles back into the beer after fermentation. In the past homebrewers thought that if you blew this gunk off you would profit from cleaner beer. Some people feel that the blow off beers lose some degree of bitterness, as the oils are lost with the krausen, but it might not matter so much in the long run.


What is a blowoff tube and how do you make it?

One method is to use a section of 1/2" tubing and wedge it into the inside of a 3-piece airlock (you have to remove the plastic bubbler piece.) Another more popular method is to use an orange carboy cap and attach a section of 1/2" tubing. We have used both methods, never had a problem with either, but would prefer the carboy cap because the tubing is easier to clean and the cap attaches to the carboy with a better grip creating a better seal. We do sell line brushes to clean lines with. Anyone who wants to use large quantities of fresh fruit in the primary will want to use a blow off tube to avoid clogging an airlock. You might even want to have a double blow off using 3/8" and 1/2" tubing on our carboy hoods.(We recommend adding fruit to a secondary fermenter to avoid this.)


My airlock blew off during a violent ferment. Is my beer ruined?

The beer is fine. When a ferment is going this wildly it is pushing off so much CO2 that no other microrganisms can fall in and contaminate it. Also, the yeast are replicating so face that if any wild yeast or bacteria fell in most likely it would be consumed by the yeast. Take the airlock and stopper, sanitize and clean them, and reinstall. Have a pint of beer! Trust us you will have many more yeast explosions in your homebrewing career. Something to remember is every yeast ferments differently at unique temperatures.


My airlock blew off. What causes a ferment to be so violent?

There are usually a few contributing factors to a violent blow off of your airlock. First is the yeast selection. Certain yeast have a greater propensity to create a "big fluffy head". The yeast that are known for big head productions are White Labs Trappist, WLP300 Hefeweizen, and WLP002 English. Certainly the first two are the most infamous. However, once in awhile we will hear of a yeast like the normally calm WLP001 California busting out of a carboy. A second factor is heat. They yeast go wild when they get hot. Fermentation above 73 degrees are candidates. Another factor is starting gravity. Higher gravity beers have more violent ferments. Sometimes a beer will start to ferment and come to a near halt shortly after starting because of a rapid drop in ambient temperature. When it suddenly becomes warm, because the weather heats up or the carboy is moved to a warmer location, it can cause a yeast breakout. If you plan on brewing with actual fruit in the primary (when lots of sugar are left) you should use a blow off that has a tube inner diameter of at least 1/2". As you can see there is no solid rule for when it will happen but there are certain factors that can be avoided. Don't ferment in a 5 gallon carboy with only an airlock as your primary fermenter. Keep an eye on your fermenter when in doubt.


What are the advantages/disadvantages of a carboy versus a bucket?

The advantages of a bucket is that it is very affordable and easy to use. The bucket fermenters that come with our kits have a spigot about 1" up from the bottom. The advantage of this is that it when it comes time to transfer one simply flips open the valve, effectively eliminating siphoning. The trub, or solid matter, gets left behind since it has settled out below the spigot level. The main disadvantage of plastic fermenters is that in the long run sanitation becomes an issue. Any scratches will harbor bacteria that a sanitizing solution may not be able to get to. Also plastic should not be used for the long term storage of beer. While plastic is very good at holding liquid in, it is not so good at keeping oxygen out. Oxygen actually seeps through the plastic walls. Glass has the advantage of being clear. You can see the marvelous yeast performing their destiny. Fermentation truly is a miracle that you probably don't want to miss viewing. Glass barring breakage will last forever and can be cleaned to a clean finish every time (with a little effort.) The disadvantage of glass is that it is a little more expensive up front and requires some additional equipment, a carboy brush for cleaning, a funnel for wort entry, and siphoning set up for getting the beer out. Glass also breaks and when wet it can be very slippery. (When the carboy does not feel round anymore get your hands out of the way! There is nothing left to catch and they crash very violently. We know many people who have ended up in the emergency room!) If you just want to get your feet wet, are buying an equipment kit as a gift and the recipient did not ask for the kit, or you live out of the country (glass does not make it so well overseas) go with the plastic. You can get a glass carboy later on. One thing to keep in mind is if you do have a bad back go with the plastic as the glass is too hard to lift.


What is a Diacetyl Rest?

A diacetyl rest is used when making lagers and ales. After a beer has fermented to near final gravity the beer is raised from fermenting temperature to a higher temperature roughly 3-4 degrees Fahrenheit above the original fermentation temperature and allowed to sit for two-four days. The purpose of this higher temperature rest is to allow the yeast to reabsorb their diacetyl that is naturally produced during fermentation. While yeast will absorb diacetyl at colder temperatures as well, the absorption happens much faster at warmer temperatures when the metabolic activity of the yeast is speed up. This quick absorption of diacetyl may help to lower the overall necessary aging time and help make a cleaner tasting beer.


At what temperature should I ferment my beer?

First we need to know whether you are fermenting an ale or a lager. An ale will typically be best at a temperature of 62-72 degrees. Most ales excluding Belgians ferment cleaner beer at the lower end around 62-66F. A lager will typically ferment best between 48 to 54 degrees. Those are just ranges in which most ales or lagers will perform appropriately. There are no exceptions where certain ale yeast can ferment below 62 degrees and there are certain lager yeasts which can ferment above 55 degrees. Every yeast has a recommended temperature range. We suggest you research your yeast strain before fermenting to understand its temperament. Get to know your yeast! They're our friends!


How can I precisely control fermentation temperatures?

In order to brew ales in hot weather and lagers in warm weather it is best to ferment in a consistent, temperature controlled environment. This can be achieved for very little money by acquiring a used refrigerator or freezer along with purchasing a Temperature Controller from MoreBeer!. How it works is simple: The refrigerator plugs into the controller and the controller has a sensor that goes into the refrigerator (the sensor fits through the door seal so no drilling is necessary.) The temperature is set on the controller and the refrigerator or freezer is turned off and on to maintain the set temperature. Check out our paper catalog in the fermentation section or by searching on MoreBeer.com for product number FE600 you can read more about how the Controller works. Also, check out our digital Ranco temperature controller(FE610) and Stopper Thermowell (FE612). This will keep your fermenting beer within 1 degree of your set temperature. Sweet!


What kind of effect can fermenter geometry have on fermentation?

This is an advanced question and one which won't really affects us as homebrewers due to our limited type of fermenting vessels. Certain designs have effects on flavor. For example, a wide fermenter, such as those used by Samuel Smith, will cause more ester production due the amount of surface area available for the yeast to settle on. There are also effects on the speed at which the yeast will clear, the shallower the fermenter the less time it takes for gravity to pull yeast to the bottom. In commercial brewing a tall, skinny fermenter will give off different esters than a carboy or bucket will. In addition, a tall, skinny fermenter can stress yeast and contribute different esters - ideal for Belgian beers! The only way to truly know what the geometry of a fermenter contributes to a beer, is to use two fermenters with the same yeast strain, fermented at identical temperatures.


How long will my lager fermentation last?

It depends on the yeast strain and temperature conditions, but you can expect fermentation with a lager to be done within four weeks. This is not a hard and fast rule. You may have fermentation that is done in as little as two weeks as well. We recommend a minimum primary fermentation at 48-50F for three weeks and a diacetyl rest for three days at 54F. For all lagers it is best to make a yeast starter 48 hours in advance to give your yeast time to replicate in preparation for a cold environment. Don't be alarmed if you don't see krausen (foam) for 2-3 days after pitching yeast this is normal behavior for lager yeast.


How long will my ale fermentation last?

It depends on the ale yeast strain and temperature conditions, but you can expect fermentation with an ale to be done within two weeks. This is not a hard and fast rule. You may have fermentation that is done in as little as three to five days. Remember: Just because sugar has been consumed and your final gravity looks complete, doesn't mean your yeast have completely re-consumed their byproducts. Fourteen Days in the primary fermenter gives most ale strains time to ferment completely, leaving behind a clean beer waiting to be consumed.


Is my beer finished fermenting?

If you have waited two weeks for an ale, or four weeks for a lager, or you're just curious. Most veteran homebrewers will tell you the beer is done once the airlock stops bubbling but this isn't a sure thing that fermentation is complete. This is where a hydrometer is sometimes worth its weight in gold. If you call our advice line and ask "Is my beer finished fermenting?" the first question will be, "Have you taken a hydrometer reading?" A hydrometer reading at the end of fermentation is called a final gravity reading, often abbreviated "FG". This tells you the amount of sugar left in the beer. Most yeast strains consume 65-75% of sugar in solution, this is called "attenuation." Here's an example gravity: OG: 1.050 your Goal FG would be: 1.010-1.015. If you are more than a few points above your estimated FG you will need to wait a couple more days. After a few days take another reading to see if the FG has dropped. If the FG has not dropped you will either need to consult us on our advice line at 925-671-4958. We will ask you some questions about the recipe, the yeast strain, and the fermentation temperatures your beer was exposed to. Sometimes we have some insightful comments on why fermentation is acting strangely, and other times only the beer Gods know.


It has been 2-3 days and my beer has not started fermenting?

Our first response to this questions is, "Are you fermenting in a plastic bucket?" 8 times out of 10 when we get this question the problem is that the lid is not securely fastened onto the top and the CO2 is coming out of the crack in the lid and not through the airlock. Our lid does not include a gasket for sanitary purposes. Make sure the lid is "snapped" into place evenly around entire circumference of the bucket. If the lid is not the problem, we will want to know your gravity reading (you will need a hydrometer to take a gravity reading). Sometimes with the right yeast strain and temperature, a yeast will ferment so fast, that fermentation completes before you check your fermenter for activity. On the flip side, If the gravity hasn't lowered from the original gravity, we will want to know which yeast strain you used and what temperature you pitched at. Note: All lager and ale yeast strains behave differently. Even the original gravity of your beer can affect the lag time of your yeast to start fermenting. The amount of nutrients like oxygen, zinc, nitrogen and can affect yeast strains behavior. To play it safe, always make a yeast starter aerate your fermenter with oxygen, and always use temperature control. Many brewers blame yeast freezing in transit. It is actually very rare for yeast freeze and completely die in shipment. It does happen occasionally. If it does you will need to make a yeast starter or pitch a fresh pack. For a couple dollars it's worth keeping a dry yeast in your refrigerator just in case.


My beer started fermenting, then stopped, and then started again?

This usually happens when the beer goes through temperature changes. The yeast stops fermenting when it gets cold as the metabolic activity of the yeast slows down. It then proceeds to start up again when the fermenter warms up. If your fermentation gets stuck warm up the beer to the desired temperature range for your yeast. Sometimes it helps to give the carboy a swirl. DO NOT add oxygen.

If there is one step you do as a homebrewer, investing in temperature control equipment will be the best thing you ever do for your beer.


Should I use a secondary fermenter when making an ale?

We answer this question a lot because we don't mention the use of secondary fermenters in our instructions and other instructions do. First lets take a look at the supposed benefits of secondary fermenters. The first one we have always read was that the beer would clear out more in the secondary. This is not true. A beer will clear just the same in a primary as it will in a primary/secondary. Another benefit is supposed to be less trub in the bottles. If you you use a racking clip and siphoning set up you should get no more trub pick up in the primary than in the secondary. The most legitimate argument for a secondary fermenter is that you remove the beer from the trub. However we have researched quite a bit of material and have done a fair amount of actual testing and can find no evidence of trub breaking down within two weeks to a point where this an affect on flavor.


How does one ferment in corny kegs?

Fermenting in a corny is the same as any other fermentation vessel with a couple of added issues. The first issue is the blow off. You can under fill a keg (3-4 gallons) and use a hose from the gas-in fitting to a bucket of water. The drawback to this method is the gas-in fitting is easily clogged if there should be major krausen formed.

The other issue is being able to rack off the yeast. We have used three methods to accomplish this task. One is to hook a piece of clear line to the beverage-out fitting and push the yeast out first. (If you are ambitious you can save this yeast for the next batch.) When the beer is running clear you start to collect the beer. The second method is to shorten the dip tube to above the yeast. This can be done with a tubing cutter. Usually 1/2" to 5/8" is enough. The third method is to use a racking arm mounted into the keg lid. You start the transfer and lower the racking cane until you just see yeast start to transfer and then you raise the racking cane slightly. Make sure to disassemble the fittings and sanitize them each time.


What happens if the ferment temperature is lower than the optimum range?

Your ferment will be very sluggish, as the activity of the yeast is halted by colder temperatures. The yeast eventually become dormant, stop fermenting, and drop to the bottom of the fermenter. To resume normal fermentation, heat the wort to the optimum temperature range and swirl it to mix the yeast back into suspension.


When should I see the signs of fermentation?

If White Labs or Wyeast fermentation will begin 5-15 hours after pitching. As the yeast nears its 4 month shelf life fermentation will begin somewhat later, usually between 15-20 hours. The first sign of fermentation will be a raised airlock. This signals CO2 production. A fine layer of foam will begin forming on top of the liquid. Within a few hours the head of foam will become thicker and rocky , and the airlock will rapidly expel the CO2 gas. Fermentation will usually be complete in 7-14 days, depending on the strain, starting gravity and ferment temperature.


Is secondary fermentation something I need to do? What is it?

Secondary fermentation on ales is something that a lot of people do because that is how most of the older homebrewing books taught people how to ferment. The theory was that you remove the yeast and trub from the ferment so that you have less flavor impact on the beer, and that less sediment would make it into bottles. More recent books and literature has proven that single stage fermentation for 2 weeks without racking yields great results without any added off flavors from the yeast and trub. Also, we notice that in that time frame the yeast has enough time to compact, so when the wort is racked to the bottling bucket or keg, most of yeast stays on the bottom of the fermenter. This procedure usually is beneficial to the brewer as it is less work and less chance of exposure to bacteria and oxygen. This method has proven very successful to thousands of our customers so far, however, we invite you to try both procedures and draw your own conclusions to which method you prefer.


When and how do you remove the trub and yeast from the conical fermenter?

Brewer's follow their own unique schedules for dumping trub and yeast based on their style of beer made. Our general plan is to dump trub after the initial ferment has started to slow down. This removes a majority of the trub, the main item we are trying to eliminate. After a few days we sometimes harvest yeast after dumping the initial trub. Sometimes there is only one dump, sometimes a few. Some brewers who use a hop back find they have so little trub it is not worth doing a dump at all. Some lager brewers do a cold settling (usually overnight) where they actually dump trub (hot and cold break) before adding the yeast. When dumping, people may use our FIL90 sanitary air filter. It fits into a stopper which fits into the fermentation lid. Thus when air is pulled back in to the fermenter during a trub drop the air is sanitary. Dumps done as fermentation subsides are less risky because of the continued CO2 production from the fermenting wort. Some customers fit a balloon onto a hollow rod and insert that into the stopper before doing dumps. The balloon fills up with CO2 and then when you dump out the bottom CO2 is sucked back in instead of air. Some brewers hook up to their CO2 system when doing a dump to force in CO2 as a replacement gas instead of air. There are many ways to use a stainless conical effectively!


Should I oxygenate my wort?

This is a big question. We will try to cover it briefly here. There is a huge body of literature written on this subject both for homebrewing and professional brewing. Why add oxygen at all? Yeast has two metabolic pathways. The one it prefers is to eat sugar and O2 to make CO2 and water. This is a very high energy pathway and it is much preferred by the yeast. It will continue on this path until all O2 or sugar is depleted. Since there is so much energy available in this pathway the yeast will use this excess energy to reproduce and also to replenish it's glycogen reserves. The second pathway, called fermentation, the yeast takes sugar and makes CO2 and alcohol. This is our favorite pathway. :) We add O2 in order to get new healthy cells and also to have the yeast with as much glycogen as possible for the main ferment. The higher the original gravity is, the more glycogen (therefore the more O2) will be needed to keep the yeast healthy until the end of fermentation. Under-oxygenating will cause all sorts of off flavors and is much more of a problem that over-oxygenation. When yeast has too low of glycogen reserves it will be "stressed" during ferment and not complete it's pathway to alcohol leaving intermediate chemicals behind. This can include esters, fusel alcohols and diacetyl. How can I add O2? Splash racking or shaking the carboy is the first method homebrewers try. It only adds a small fraction of the O2 required by the yeast but it is much better than doing nothing at all. The other disadvantage is you are shaking outside air in and it could be contaminated with organisms. The most likely is wild yeast. Injecting air through a sanitary filter is another method. This is the method used by Anheuser Busch. It works well for yeast strains with low O2 requirements and also for low gravity worts. The advantage is that it is hard to over-oxygenate. The disadvantage is it is impossible to get enough O2 in for a barley wine or a double IPA. And it is only close to good enough for a regular IPA. The rule I was taught was: Air is Ok to 1.044 but not past. Injecting O2 directly. This allows you to set almost any O2 level you desire. However it is very important not to over-oxygenate as this is quite easy to do with pure O2. You only want enough O2 to quadruple your yeast, any more will start to strip flavor components from your wort and leave the finished beer tasting watery. With a flow meter it is very easy to control the amount of O2 you inject into your wort. In the brewery I work in I have a constant wort flow rate, wort temperature, oxygen flow rate and length of hose that allows me very repeatable results when I oxygenate during cooling.


What is the difference between oxygenation and aeration?

Oxygenation involves injecting the wort with 99% pure oxygen. Aeration involves injecting the wort with air, of which only 21% (by mole) is oxygen. Both obtain the same end result of supplying the yeast with oxygen. Aeration will take longer and if you are using a small fermenter foaming may be an issue. Budweiser will not use pure oxygen because they feel it "is difficult to be consistent". However you could not get enough oxygen from air to make a Barley Wine.


Why and how should I add oxygen to my un-fermented wort?

Yeast consume oxygen during the aerobic replication process. The objective is to build strong cell membranes capable of withstanding higher alcohol contents, and also to build up metabolic energy used during later anaerobic fermentation. In oxygen-depleted wort conditions (zero oxygen), yeast will reproduce only to approximately half the number of total cells possible. In oxygen-deficient wort conditions (low oxygen) you will experience unwanted longer lag times, higher ester levels, and higher residual gravities. Higher gravity beers have even greater requirements for oxygen. So, how do you get oxygen into your wort? A simple way is to rock or shake the carboy for 5-15 minutes. Another way, is to use the Fermentap Siphon Spray Wort Aerator. These methods, while labor intensive, effectively dissolve an acceptable level of oxygen into solution. For even greater oxygenation, use either a MoreBeer! Oxygenation System (Ideal) or a MoreBeer! Filtered Aeration System.


I would like to use a digital temperature controller but I am working with 220V?

You will need to order the FE610A un-wired Ranco controller and wire it yourself. This only includes the controller itself and not the AC wire or the outlets. They are compatible with 120/240V and 50/60hz.


At what temperature should I add a lager yeast?

There are two methods of pitching lager yeasts. Brewers use both methods with success, but each brewer tends to have a preferred approach. A) Starting Warm then Cool Down. This is the easiest method for the average homebrewer. Pitch yeast at 60-65F, reduce the wort temperature 10F per each 12 hours until reaching the desired fermentation temperature of 48-54F. This method works well without forming high amounts of esters because most esters are produced after the first 12 hours. B) Starting Cold using Twice the Yeast, or use a Yeast Starter to "Quick-Start" Fermentation. Pitch four vials of yeast at the recommended fermentation temperature (48-54F). Or, use a Yeast Starter (see next page), to make a 1-2 liter yeast starter per each 5 gallons. Lager yeast ferment well at this temperature, but they grow very slowly. If you use this method, fermentation activity won't show for 48-72 hours. Cli


What is flocculation?

Flocculation: This refers to yeast's tendency to clump together at the end of fermentation and drop to the bottom of the fermenter. Yeast strains are separated into three main degrees of flocculation: High, Medium, and Low. A yeast strain that has low flocculation will take a longer time to settle-out of solution, possibly resulting in cloudier beers. A yeast strain with high flocculation will settle-out rapidly, resulting in beers that become clear much faster.


What is attenuation in reference to yeast?

Attenuation: The percentage of sugar that a yeast will be able to ferment. Low-attenuation yeast result in maltier beers. High-attentuation yeast results in drier, less sweet, beers.


Is PET and PETE the Same Resin?

Yes PET and PETE refer to the same material, Polyethylene Terephthalate. You can also check out the Wikipedia page for Polyethylene Terephthalate at: http://en.wikipedia.org/wiki/Polyethylene_terephthalate


Is your Plastic PET Carboy as good as the Better Bottle brand carboy?

We think it is actually better. While both are of great quality, this PET carboy is thicker and does not have ribs. The thicker walls could lead to less oxygen ingress (not proved) and not having ribs makes it easier to clean. Our PET Carboys are made by the Vintage Shop in Canada and they had a lab do some analysis. You are welcome to check it out here: Product Comparison Data http://www.thevintageshop.ca/allproducts/Evaluation%20of%20PET%20carboys%20-%20090918%20final.pdf Analysis of Differences http://www.thevintageshop.ca/allproducts/Evaluation%20of%20PET%20carboys%20-%20090918%20final.pdf


How do I add real fruit to my beers?

Ultimately, the quantity of fruit used will depend on the flavor you are looking for.  As a starting point we recommend using two pounds per 5 gallons.  Cut up the fresh fruit, remove any pits and place in the freezer.  Freezing helps extract more flavor and will also reduce any microbial activity . When you are ready thaw it out, mash it up if appropriate, and add to your secondary fermentation for a week, give or take. Using our R395 to filter out fruit, siphon the beer out of your fermenter and into a keg or bottling bucket. 


I brewed a week ago, and my beer STILL has a krausen on it?

No, some yeast strains form a tight krausen like that - the beer is perfectly ok!  Take a sample, and if the beer is done (has reached approximately 25% of its starting gravity) your can proceed with racking it into your keg or bottling bucket. Don't worry about the krausen at all. 


What happens if I add dry yeast directly to the beer?

Only 50% of the yeast cells will survive the rehydration process if added directly to wort.  Your beer will still ferment but there is a much higher chance for a stuck fermentation, high residulat gravity, and the flavors produced by the stressed yeast will not be as good.  We recommend you follow the reyhdrations instructions on the yeast packet.  


My airlock is not bubbling?

I can see my beer fermenting, but there are no bubbles in the airlock - why? Inspeck the airlock for a crack in the stem of the airlock. If that is not the problem make sure that stopper or the lid on your container is seated properly.  Bucket lids are particularly problematic to thoroughly seal. If you are brewing in a conical fermenter try adjusting the clamp and/or lid gasket. 


Can I Use The Plastic Speidel Tanks for Storing Wine?

We would not hesitate to use these for wine storage for 6 months, give or take depending on the kind of wine and the size of the tank (more on that later). Speidels are made from thick HDPE, the same material as Flextanks are made from. For those not familiar with Flextanks these are similar HDPE tanks made for wine storage that have similar oxygen transfer rates to oak barrels. So the idea is that you can store wine with in these types of tanks with oak and get similar results to the slow micro-oxygenation you get with a barrel. We would suggest for longer term storage you remove the airlock and attach the threaded cap. Depending on tank size, more oxygen transfer will occur through the airlock than will through the sidewalls of the tank.

When we were considering these tanks for sale we were hesitant about long term wine storage as well even though we knew about the material and the science. One real life example was that in Germany these Speidel HDPE tanks can be found in nearly every winery for left over small lots. In a winery we visited in the Mosel Valley they had high-quality Riesling stored in the larger size speidel tanks for a year. 

If you are making a wine kit the micro-oxygenation is going to play less of a factor since kit wines are designed not to require long term aging. If you are making a high tannin red directly from grapes you will want some micro-ox in your vessel. If you store in a carboy or stainless tank your wine will go reductive and is more likely to develop sulphur based compounds that reduce the perception of ripe fruit. For big reds where barrels are not an option, the Speidel HDPE tanks are ideal. 

With that said the larger the HDPE vessel the less overall surface area. So if you have a larger size tank and a big red wine you can leave it in there longer. If you have a more delicate wine (white, pinot, etc) and a small tank you should leave it in for less time. It would be great if we could say for this type of wine and that size tank here is a rough estimate of months you could store. While we want to work on that more it will always come down to taste as every wine is going to react differently.