Beer > Amateur
How much yeast is in my White Labs homebrew PurePitch®?
The wording on our PurePitch® packaging - 'Made to Contain over 100 Billion Cells' - is a target cell count number for each of our yeast packages. We specifically say, “Made to Contain” because not all packages will contain more than 100 billion cells even though we target that number in our production and packaging processes. This is because the reality of cell biology is that cell sizes vary, cell packing varies, and since cells are microscopic, those small variations lead to large fluctuations in cell numbers.
Although the Pure Pitch® packages state a cell net volume of 35 mL - the packages contain a minimum of 40 mL. With the actual volumes ranging from 40 to 50 mL. Due to this reality, we will be adjusting the stated net volume on our packaging to reflect the 40 mL amount.
In our production, we allow for cell counts of 1.5 to 3.0 billion per milliliter which will produce 60 to 120 billion total cells if 40 mL. We target the high range of cell counts and fill volumes in our production and packaging processes. However as stated above, the reality of cell biology is that those numbers will vary.
We publish the QC data that includes the actual cell count of each lot on Yeastman.com. We state on Yeastman.com the allowed cell count range (1.5 to 3.0 billion per milliliter) because it accurately reflects the reality of packaging microorganisms.
What is brewer's yeast?
Brewer's yeast is a single celled fungus that ferments from the top or the bottom and reproduces asexually by budding. They are unique in the world of yeast and have essentially been domesticated. Brewer’s yeast is used to make beer, wine, bread, and any other fermented beverage, food or product. Certain strains work best with certain beers and other products- contributing the flavors the public anticipate.
We sell White Labs yeast. Do you have any suggestions for how I should ship the yeast to my customers who order by phone or online?
White Labs is committed to producing the highest quality of yeast in the world. It leaves our laboratory having undergone the most rigorous standards of quality control. But much can happen in the shipping process, and to remain its best, it’s important to be handled well. To ensure the yeast reaches your customers in the same quality as when it left our laboratory, we’ve put together a set of shipping guidelines.
1. The most important rule is, keep it cold! Yeast needs to be stored in a refrigerator at all times (40°F, 4°C). Its shelf life can decrease drastically when left outside of this range. Too cold is just as damaging as too hot and it should never be frozen. Yeast loses 10% viability each time it is frozen.
2. Insulation and Ice Packs. The more insulation inside the package when shipping the better. Insulation is used both as padding for protection, and to regulate the internal temperature. At White Labs, we pack each shipment with ice packs to ensure that it will stay cool during transit.
Provided below is a table of the recommended ratio of homebrew containers to ice packs needed when shipping.
VIALS/PurePitch ICE PACKS (normal) ICE PACKS (hot months)
1-4 1 2
5 to 9 2 4
10 to 19 3 5
3. Packing Sequence. Be sure to remove the yeast from the refrigerator right before packing it in a box. Ice packs only keep the yeast at its current temperature, it will not chill the yeast. If you package the yeast at 40°F (4°C) with ice packs and insulation, it will stay close to that temperature for the first 24 hours. If the yeast temperature rises to 50°F (10°C) before packaging, it will never get back to 40°F (4°C). The ice packs will maintain it at the higher temperature, and the yeast will rise to higher temperatures more quickly than if packed at 40°F (4° C).
4. We recommend shipping everything 1 to 2 days. Be aware of weekends and holidays where shipments can be delayed. Plan your shipments during the week to ensure delivery before the weekend.
5. Make sure to let you customers know that it needs to be refrigerated upon arrival.
By following these recommendations, you will pass on the highest quality of our product to your customers. We thank you for taking the time to ensure these steps are followed.
I have heard that Rochefort has two strains. How would I go about selecting those as two different strains (separating them)? How do you differentiate between the different strains?
This is a topic that is subject to a lot of rumors. You can find multiple strains in a yeast slurry, but it can still be one strain that is doing all or most of the fermentation. If you wanted to look at Rochefort specifically, if you had the yeast slurry you could plate a bunch of times and select individual colonies, then conduct fermentation and taste the results. You can also do differential plates or giant colony plates but that is more involved. If you have yeast from the bottle, there is really little you can do because often you find a lot of other yeast and organisms in the bottle that are not intended to be there.
The yeast took longer than expected to get to me, as I live in India. What should I do?
White Labs has shipped yeast around the world for years with very few problems. Our yeast packaging and shipping protocols are designed to keep the yeast in good shape even if it takes one week for shipping.
How much yeast should I pitch?
Please visit: www.whitelabs.com/resources/homebrew-starter-tips
Do you have a map between your yeast strains and others?
No, we do not have a direct “correlation chart”. Some of our strains are similar to those offered by other companies, but some are different. Even for the strains with similar origin, they have been obtained at various times from differing locations. They are stored differently, grown in different conditions and in different media. Each yeast strain produced by White Labs has been carefully selected from breweries worldwide, and further selected for advantageous brewing characteristics. In general, yeast strains of similar origin exhibit similar, but not exact properties. In our descriptions of the yeast strains, we describe the area of origin and the flavor profile parameters of each strain.
How can I obtain White Labs yeast if my local homebrew shop doesn’t carry it?
If your local homebrew shop does not carry our yeast, you can simply order the yeast you need off the order now section of this website.
What is the shelf life of White Labs Yeast?
Every package of White Labs PurePitch yeast -- homebrew and commercial versions -- have best before dates and lot numbers (these lot numbers can be entered into Yeastman for testing data, regardless of package size).
How can I increase the oxygen level in the wort?
Most homebrewers add oxygen into wort by shaking the carboy. This can only achieve 10-30% of desired dissolved oxygen levels. Commercial brewers force oxygen into wort using an inline aeration stone. Homebrewers can find oxygen stones at most homebrew shops.
How should I store my yeast?
Yeast should be stored in the refrigerator prior to use. Remove the yeast from the refrigerator approximately two to six hours before pitching and allow the yeast to come up to room temperature. The reason for this is to prevent a temperature shock when the yeast is pitched.
Can I use your liquid yeast to make bread?
Yes, you can use our yeast to make bread. It will take longer to rise, perhaps overnight, but you will have interesting almost beer like flavors in your bread.
What is flocculation?
Flocculation refers to the clumping of yeast cells at the end of fermentation. Strains are separated into three main degrees of flocculation- High, Medium, and Low. An example of a highly flocculent strain would be our English Ale yeast, which will settle at the bottom of the fermentation tank. An example of low flocculent strain would be our Hefeweizen yeast.
Is overpitching yeast harmful?
If the beer is overpitched the yeast does not grow through a completed growth cycle. This results in a few new yeast cells which makes for unhealthy yeast and creates low viability by the end of fermentation.
What is diacetyl?
Diacetyl is a natural byproduct of yeast. It is most commonly recognized as a butterscotch or buttered popcorn flavor in the beer. To minimize the diacetyl attributes in beer, it is recommended that the fermenting wort rest once the beer has reached terminal gravity for 48 hours at 62-70°F prior to crashing the temperature. This stage allows the yeast to reabsorb the diacetyl.
Can I combine yeast strains? Will there be any benefits or drawbacks from this?
Yes, some brewers like to combine strains for more unique flavor profiles. For example, a mellow Hefeweizen beer can be produced by combining WLP001 California Ale Yeast with WLP300 Hefeweizen Yeast. Some of the benefits of blending yeast strains would be to blend flavors or aromas of different strains. Over time one strain can dominate the other; thus causing the consistency of flavors to be lost over time. If flocculation is different from strains it is hard to collect an equal amount of each strain.
Why does my beer have a high ester and/or sulfur level?
High ester and sulfur levels are most commonly associated with high fermentation temperatures. Different types of strains also produce different ester and sulfur attributes. Make sure you choose the proper yeast for the style of beer you are making and ferment the wort within the recommended temperature ranges.
What is meant by "certified pure yeast"?
White Labs certifies the yeast to be free from aerobic bacteria, anaerobic bacteria, and wild yeast contamination through a series of tests performed by our lab. Yeast does not leave our facility unless it is free of contaminants, and at least 95% viable. A signed report is shipped with each batch of yeast to commercial breweries. For homebrewers, the yeast vials come from a lot that is tested, and the report is housed at White Labs.
How long does the fermentation take to complete?
Most fermentations will be complete within 14 days. Lager fermentations can take up to one month, plus aging time. The typical ale profile is to ferment very actively for 1-4 days, which is called the “exponential” or “log” phase. Then the yeast enters a stationary phase, which helps to mature the beer and can last from 3-10 days. The beer should be ready to bottle at this time. It is important to check the final gravity (FG), and calculate the percentage attenuation to make sure the fermentation is complete. If the particular yeast strain is not very flocculent, it is hard to gauge when fermentation is complete without calculating attenuation %.
What is Servomyces?
Servomyces is a nutritional yeast supplement (GMO free) that was originally developed for German brewers by Weihenstephan and the Munich University. It conforms to the restrictions of Reinheitsgebot. Servomyces enables any yeast strain’s ability to incorporate essential nutrients into its cellular structure. It is propagated in a micronutrient rich environment and then killed off prior to packaging. Boiling incorporates the servomyces into the wort. The benefit of servomyces is that micronutrients, e.g., zinc are able to pass through its cell walls to your live cell yeast cell, thereby delivering the micronutrients without toxicity. Because this system is so effective in eliminating autolysis and improving the health of your yeast- it should be used in every batch. Servomyces is tested in breweries around the world, and has been proven to:
Cut down fermentation time
Greatly reduce harsh sulfur notes
Improve the health and viability of yeast
Reduce levels of diacetyl at the end of primary fermentation
Produce faster, more complete attenuations
Increase yeast production for a better harvest
Improve the quality of the finished product
Servomyces can be used in all fermentations, including beer, wine, cider, and mead.
Each retail packet contains 6 capsules, which can be used for a 5-gallon (20-25L) batch of beer, wine, mead or cider. The instructions are as follows:
1. Add 1 capsule 10 minutes prior to the end of the boil.
2. If your fermentation does not require a boil, open the capsule and pour in the servomyces, since the capsule requires boiling to melt.
3. Only one capsule is required per 5-gallon (20-25L) batch.
4. Servomyces can be used in all fermentations including, beer, wine, cider, and mead.
I am curious to know how your nutrient may differ from Servo? That is what I use now, but since I hope to switch to White Labs yeast exclusively in the future, I was wondering if the WL product may be superior.
Our nutrient (WLN 1000) has amino acids, so if your wort is deficient in nitrogen our nutrient helps a lot. When trying to grow more yeast as done in propagation our nutrient can really help. Most of our customers use servomyces; it has a lot of useable zinc and zinc is a great source of fermentation power. If that doesn’t work, it may be a nitrogen problem, and our nutrient can help.
What is attenuation?
Attenuation is the percentage of sugars that the yeast consume during fermentation. If the fermentation went to 1.000 gravity, that would be 100% attenuation. Understanding the different attenuation ranges of each strain will help determine the terminal gravity of the beer.