Frequently Asked Questions

Home Enthusiast & Retailer Frequently Asked Questions

We strive to answer all of your yeast related questions. If you have not found your answer on our site, please contact your local home brew shop or point of purchase for more information regarding Wyeast products or concerns. If you are a commercial or retailer client, please login to contact customer service.

Click on each question to link down to the answers.

  1. The Wyeast package at my LHBS is slightly swollen. Is it still OK to use?
  2. Is the yeast in the small inner packet or in the foil pouch itself?
  3. Can I use an Activator package without activating it and waiting for it to swell?
  4. Does the package need to be fully swollen before pitching?
  5. Does the cell count increase when the package is activated?
  6. How long should it take for a package to swell?
  7. Do I need to make a starter for an Activator?
  8. I popped the inner nutrient pouch and the package swelled tight but I can’t use it right away. What do I do?
  9. I pitched my yeast and I’m not seeing any activity in my blow-off or airlock. What should I do?
  10. Is the air-lock a good indicator of how a fermentation is proceeding?
  11. I brewed a high gravity beer, can I re-pitch the yeast from this batch?
  12. I brewed a high gravity beer and I am having a difficult time getting the beer to attenuate. What went wrong?
  13. Do you need more yeast for high gravity fermentations?
  14. My fermentation took longer than normal to complete. Is my yeast bad?
  15. What should you do if there is no activity in my carboy in the first 24 hours?
  16. What temperature should I pitch lagers?
  17. I’m brewing a lager, do I need to cool my wort to fermentation temperature before adding the yeast?
  18. What should you do if the yeast is frozen?
  19. What strains are typically slow activators and slow starters in fermenters?
  20. Why does Wyeast sell smack packs rather than tubes?
  21. What if I want a strain that is not offered in the Wyeast’s normal line-up?
  22. If there is a problem with the yeast performance, who should the customer contact?
  23. If a retailer is shipping yeast, how should it be packaged?
  24. What is the best way to store yeast before use?
  25. What should the gravity of a starter be?
  26. What are the causes of swollen packages? Can you sell them?
  27. What questions should be asked to a customer that has a problem fermentation?
  28. What are optimal levels of O2 in wort?
  29. What is the maximum level of O2 you can get in a carboy using air?
  30. Approximately how long do you have to shake a 5 gallon (19 L) carboy to get oxygen saturation (8ppm)?
  31. How long do you have to run a stone with an aquarium pump to achieve O2 saturation (8ppm) in 5 gallons (19 L) of wort?
  32. How do you achieve higher than 8 ppm O2 levels in your wort? .
  33. What factors are associated with ester (fruity) production?

     

Answers

1. The Wyeast package at my LHBS is slightly swollen. Is it still OK to use?
Yes. Trace levels of fermentable carbohydrates or CO2 in yeast slurries at the time of packaging may cause a slight expansion in packages. “Off gassing” is a result of a small amount of metabolism or simply CO2 being released from the media and can occur with proper storage. This does not indicate the mishandling of the product or a decline in the health or purity of the culture. Some strains, including 1056 and 1388, are more prone to “off gassing” than others.
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2. Is the yeast in the small inner packet or in the foil pouch itself?
The yeast is in the main foil pouch. The small inner packet contains the sterile nutrient and wort that feeds the yeast before it is added to your fermenter. 
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3. Can I use an Activator package without activating it and waiting for it to swell?
Yes. An Activator pack has enough yeast in it to pitch 5 gallons (19 L) whether it is activated or not. There will only be a slightly longer lag time if the package is not activated before use. In any case, the nutrient pack should be popped before using because it contains valuable nutrients. Typically, the Activator can be activated when you start your brew and will be swollen by the time your wort is cool.
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4. Does the package need to be fully swollen before pitching?
No, The package can be pitched before activating, or at anytime during the activation process. The activation process "jump starts" the culture's metabolism, minimizing the lag phase.
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5. Does the cell count increase when the package is activated?
The cell count does not increase significantly when the package is activated. The smack-pack is not designed to dramatically increase the cell count, it simply “activates” the yeast metabolism.
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6. How long should it take for a package to swell?
If a package is within 2 months of the manufacture date, the package should show signs of swelling within 3-5 hours and typically much faster than that. When the yeast is stored for long periods of time, they slowly consume their energy reserves (glycogen). When the energy reserves get low, the yeast are slow to produce CO2 and therefore are slow to cause swelling in the package. Improper storage at warm temperatures also has the same effect as long storage times.
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7. Do I need to make a starter for an Activator?
No. The Activator is designed to deliver professional pitch rates (6 million cells/mL) when directly added to 5 gallons (19 L) of wort. (<1.060 at 70 °F/ 21 °C). However, if a package is slow to swell, suspected of being mishandled, or if the date is approaching the six month shelf life, it is a good idea to build the culture up with a starter. High gravity or low temperature fermentations require higher pitch rates. This can be achieved with inoculating with additional packages or making a starter.
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8. I popped the inner nutrient pouch and the package swelled tight but I can’t use it right away. What do I do?
If you have activated a package but can’t use it right away, simply allow the package to swell and then refrigerate the package. The yeast will survive for extended periods if refrigerated. Before using, take the package out of the refrigerator and allow it to come up to room temperature before using. It is best to use the yeast as soon as possible.
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9. I pitched my yeast and I’m not seeing any activity in my blow-off or airlock. What should I do?
Relax, some fermentations will not show signs of activity for up to 36 hours. If the fermentation is still sluggish after 36 hours take a gravity reading. It is not unusual for blow-offs or airlocks to have leaks and therefore show no activity. A gravity reading is the only way to get an accurate idea of what is happening in your fermenter. If you take a gravity reading and it still shows no activity, then try to figure out what is inhibiting fermentation. The factors that can keep the yeast from fermenting are: temperatures too low or too high at run-in, no oxygenation at run-in, pitch rates too low, or a very unhealthy yeast culture. The most common problem is the run-in temperature. If the temperature was too low, warm up the wort. If the temperature was too high, the culture is most likely irreversibly damaged and you need to pitch more yeast immediately. Oxygenation and agitation will also stimulate the yeast and speed the onset of fermentation.
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10. Is the air-lock a good indicator of how a fermentation is proceeding?
No; only by taking a gravity reading can you accurately determine fermentation progress.
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11. I brewed a high gravity beer, can I re-pitch the yeast from this batch?
Do not re-pitch yeast from a high gravity beer. Yeast left from high gravity brews is usually very unhealthy or dead and will not perform well in subsequent brews.
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12. I brewed a high gravity beer and I am having a difficult time getting the beer to attenuate. What went wrong?
There are many factors that lead to incomplete attenuation. At the beginning, it is very important to increase your pitch rates according to the original gravity of your beer. A good rule to follow is a million cells per mL per °Plato. This means that you need 20 million cells per mL for a 20 °Plato (1.080 specific gravity) beer, or 3 Activator packages for a 5 gallon (19 L) batch. It is also important to remember that it is more difficult to get oxygen into the solution in a high gravity wort. At the end of fermentation, high alcohol levels, lack of nutrients, poor yeast health and lack of fermentable sugars can effect attenuation.
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13. Do you need more yeast for high gravity fermentations?
Yes, anytime you are pitching yeast into a harsh environment (high gravity, low temp) you need to add additional yeast. A rough rule of thumb is to double pitch rates above 1.065 and triple pitch rates above 1.085. Or, more technically, a million cells per mL per °Plato are needed for a 20 °Plato (1.080 specifice gravity) beer, or 3 Activator packages for a 5 gallon (19 L) batch. It is also important to remember that it is more difficult to get oxygen into the solution in a high gravity wort.

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14. My fermentation took longer than normal to complete. Is my yeast bad?
Fermentation is dependent on many factors. The issues to consider are: How fresh was your yeast? What was your pitch rate in relation to your original gravity? Is the fermentation temperature appropriate for the yeast strain? Did you effectively oxygenate your wort? Have you calibrated your thermometers lately to be certain that your mash, run in, and fermentation temperatures are accurate? Are you using a yeast nutrient to make up for any nutritional deficiencies in your wort? All of these factors plus many more will affect the length and vigor of your fermentation.
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15. What should you do if there is no activity in my carboy in the first 24 hours?
Some fermentations will not take off for 36 hours due to many variables. Once past 36 hours, take a gravity reading, make sure that the temperature is warm, and agitate the carboy. Agitate every so often for 12 hours, then take a gravity reading to see if fermentation has begun.
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16. What temperature should I pitch lagers?
More yeast (double- two packages or make a 2L starter) is required for cold fermentations.  To compensate for this, pitch one package into 60-68 °F (15-20 °C) wort, allow fermentation to begin, and cool to desired fermentation temperature.
            
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17. I’m brewing a lager, do I need to cool my wort to fermentation temperature before adding the yeast?
There are different views on this topic. The individual brewer ultimately has to weigh the pros and cons. If a brewer is to pitch the lager yeast at fermentation temperature (55 °F/ 12 °C and below) then the pitch rate needs to be increased and a slower start to fermentation should be expected. The other option is to pitch the yeast into wort (60-70 °F/ 15-21 °C) and maintain temperature for 24 hours or until signs of active fermentation are evident and then cool to desired fermentation temperature.
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18. What should you do if the yeast is frozen?
Thaw out in fridge. Activate and assess the time that it takes to swell. If there is no activation within 24 hours, do not use. If there is activation, make a starter to revive culture.
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19. What strains are typically slow activators and slow starters in fermenters?
Belgian Ale #1214 and Belgian Strong Ale #1388  are typically slow starters.
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20. Why does Wyeast sell smack packs rather than tubes?
We feel that our Activator is the best product on the market. In addition to the oxygen and UV barrier, our packages include the activator system. This allows the home enthusiast to initiate the culture’s metabolism prior to pitching, reducing lag times. This also works as a built-in viability test.
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21. What if I want a strain that is not offered in the Wyeast’s normal line-up?
Unfortunately, Wyeast cannot make small quantities of any strain for home enthusiasts. However, if there is a certain strain that you would like to see offered, let your local retail supplier know, and they can get in touch with Wyeast. These strains can then be made available through our Private Collection* program. We base our PC* strain selections off of your requests.
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22. If there is a problem with the yeast performance, who should the customer contact?
Please contact your local retail supplier of Wyeast Laboratories products and allow them to help you identify and solve the problem. If you have a question they cannot answer, then they can contact Wyeast with your question.
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23. If a retailer is shipping yeast, how should it be packaged?
All yeast shipments should be packed with enough ice to keep the yeast cool until it reaches it's destination. Remember this is a living organism that will be damaged by extended or repeated periods of warm temperatures.
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24. What is the best way to store yeast before use?
In a refrigerator as cold as possible without freezing. 34 °F (1 °C) is ideal. Most refrigerators run around 40 °F (4°C).
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25. What should the gravity of a starter be?
The gravity for a starter should be 1.040.
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26. What are the causes of swollen packages? Can you sell them?
Swollen packages are almost always the cause of a small amount of sugar or CO2 being left in solution at the time of packaging. Upon shipment, CO2 can be released from solution or  the yeast can consume the sugar and create a small amount of CO2. Cell autolysis, or cell death can also be a cause of swelling packaged. However, this is only in rare cases where the yeast is exposed to high temperature for an extended amount of time. If a package is swollen and  has not been mishandled, it can be sold with confidence.              
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27. What questions should be asked to a customer that has a problem fermentation?
What strain, date, size of package, and manufacturing code? What is the gravity and temperature? What was the OG and pitching temp? How many hours since pitching? Did you make a starter? Method of aeration?
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28. What are optimal levels of O2 in wort?
10-15 ppm.
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29. What is the max level of O2 you can get in a carboy using air?
8 ppm.
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30. Approximately how long do you have to shake a 5 gallon (19L) carboy to get oxygen saturation (8 ppm)?
45 seconds of vigorous shaking.
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31. How long do you have to run a stone with an aquarium pump to achieve O2 saturation (8 ppm) in 5 gallons (19 L) of wort?
5 minutes.
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32. How do you achieve higher than 8 ppm O2 levels in your wort? .
By injecting pure oxygen into your wort through a stone (1 min for 12 ppm). Or, by flowing pure oxygen into the carboy's head space and shaking for 20 seconds, twice.
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33. What factors are associated with ester (fruity) production?
Decreased pitch rate of yeast, increased fermentation temperature, and increased original gravity.
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Commercial Client Frequently Asked Questions

We strive to answer all of your yeast-related questions. If you have not found your answer on our site, please login to contact customer service.

Click on each question to link down to the answers.

  1. I can’t afford to purchase direct pitch quantities, can I still use Wyeast products?
  2. I received my yeast, but was not able to use it right away. How long can I store my yeast before using it?
  3. I don’t have space to propagate; do you sell direct pitch quantities?
  4. I pitched my yeast and I’m not seeing any activity in my blow-off or airlock. Should I pitch more yeast?
  5. I brewed a high gravity beer; can I re-pitch the yeast from this batch?
  6. My fermentation is not attenuating.
  7. I propagated my yeast and then brewed in on top of it. My fermentation is very slow or has not started at all. What happened?
  8. My beer is not clearing, what is wrong with my yeast?

Answers

1. I can’t afford to purchase direct pitch quantities, can I still use Wyeast products?
Wyeast sells yeast customized to fit your needs. We will help you to determine a propagation schedule that works with your budget and your system.
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2. I received my yeast, but was not able to use it right away. How long can I store my yeast before using it?
It is best to use your yeast within 2 weeks of receipt. The length of storage will directly and negatively affect the lag time. If the yeast must be held for more than 2 weeks, it is beneficial to feed the culture before using it. Bring the culture out of cold storage and add it to fresh, well-aerated or oxygenated sterile wort (about 2 gal/7.5 L  per 1 liter of yeast). Allow the culture to ferment for 24 to 48 hours at 70 to 75 °F (21 to 24 °C) and then use the culture as you normally would
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3. I don’t have space to propagate; do you sell direct pitch quantities?
Wyeast sells direct pitch quantities for any size brewery. We customize your pitch rate to match the yeast, beer style, temperature, and original gravity.
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4. I pitched my yeast and I’m not seeing any activity in my blow-off or airlock. Should I pitch more yeast?
Always take a gravity reading before making any assumptions. It is not unusual for blow-offs or airlocks to have leaks and therefore show no activity. A gravity reading is the only way to get an accurate idea of what is happening in your fermenter. If you take a gravity reading and it still shows no activity, then you must try to figure out what is inhibiting fermentation. The only factors that could keep the yeast from fermenting are: temperatures too low or too high at run-in, no oxygenation at run-in, pitch rates too low, or a very unhealthy yeast culture. The most common problem is the run-in temperature. If the temperature was too low, warm up the wort. If the temperature was too high, the culture is most likely irreversibly damaged and you need to pitch more yeast immediately. Oxygenation and agitation will also stimulate the yeast and speed the onset of fermentation.
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5. I brewed a high gravity beer; can I re-pitch the yeast from this batch?
No. Do not re-pitch yeast from a high gravity beer; the yeast is not healthy and will give you problems in subsequent generations.
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6. My fermentation is not attenuating.
Perform a forced fermentation test on your beer to determine where the problem is coming from. If the forced fermentation does not attenuate, the wort is not fermentable.

  • Check the mash temperature and times. Did you test for conversion (Iodine)?
  • Check the mash thermometer.
  • Check the grist. If the forced fermentation does attenuate- The wort is fermentable, but the fermentation is failing.
  • What generation are you on?
  • How long did you store your yeast and at what temperature?
  • What was your pitch rate in comparison to your original gravity? (See Pitch Rate Section)
  • Have you checked your oxygenation system for leaks recently to be certain that you are achieving the level of dissolved oxygen required?
  • Is the fermentation temperature appropriate for the yeast strain?
  • Have you calibrated your thermometers recently to be certain that the temperature readings you are getting are accurate?
  • Are you using a yeast nutrient to ensure that you have adequate levels of essential micronutrients and free amino nitrogen?

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7. I propagated my yeast and then brewed in on top of it. My fermentation is very slow or has not started at all. What happened?
When propagating, it is important to pitch at least 10 million cells per mL(1 liter per barrel or hectoliter) to get a rapid, healthy start. Do not exceed a 10 fold increase in volume with each step. Allow each propagation step to attenuate 75% (take a gravity reading, confirming 75% attenuation) before brewing on top. Maintain propagation temperatures of 68-72 °F (20-23 °C) for rapid and healthy growth.
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8. My beer is not clearing, what is wrong with my yeast?
Many times protein haze may be mistaken for non-flocculating yeast. First confirm that it is yeast in suspension and not protein by performing a Haze Test.

Haze Determination Test: 

Decant 50 mL of hazy beer into a clear sample container. Add 2 mL caustic (40-50%). Shake. If beer turns clear, the problem is protein in suspension. If beer remains cloudy, yeast is still in suspension. Flocculation and clarification are very complex. Many times clarification problems have nothing to do with the yeast, but instead with the environment that the yeast is in. Yeast will flocculate and sediment given time unless something inhibits this. A combination of environmental factors including pH, alcohol content, temperature, sugar concentration, and ion content can negatively affect flocculation and sedimentation. Environmental conditions will affect the flocculation abruptly, showing large differences in subsequent fermentations. It is also possible for yeast to mutate to a less flocculent form. This is usually a very gradual process, over the course of many generations. Every time a brewer harvests their yeast, they have the opportunity to select for a slightly different population. Over a number of generations, the population can show a change in flocculation and thus probably population. It is important for the brewer to try to harvest yeast from the same area in the fermenter to minimize possible changes. (See section on Harvesting)
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