Brewer's Friend Home Brewing Software

Yeast Pitch Calculator for iOS 7 launched

Our popular Yeast Pitch Calculator is now available in the App Store for iOS7!

This is a port of our popular web based Yeast Pitch Calculator, now available for iPhone iOS7.

Pitch your yeast like the pro’s do with this easy to use calculator that supports dry yeast, liquid yeast, slurry, and starters. Calculates liquid yeast viability based on manufactured date. You get to choose your desired pitch rate in million cells / milliliter of wort / degree plato. Also calculates how big of a starter to make and how much DME to add to that starter. Up to three step-ups are supported, so you can even start from a yeast slant! Two different growth curves are supported. The first comes from recently published research at Braukaiser, and the second from a study by Chris White.

Posted in Announcements, Yeast Cultures | No Comments »

BRY-97 American West Coast Yeast Review

BRY-97 is a relatively new dry yeast on the market released in limited amounts in 2012.  Got a pack for the first time late last year. That brew is almost completely gone, and I’m happy with the results, but there were a few surprises!

In a nutshell, BRY-97 is NOT your typical Chico strain like US-04, Wyeast 1056 or White Labs WLP001.  

BRY-97 accentuates malt character and provides some fruity notes (pineapple, citrus). It also has a huge frothy krausen head and a long lag time compared to US-05.

I brewed an IIPA with it, fermented at 65F (not too cool, not too warm).  The beer was great, but I was surprised that it wasn’t a more neutral strain, like the Chico strains.  The shed smelled like pineapple the entire time it was fermenting!  The tropical note has dropped off now after several months in the bottle but there is still something sweet and fruity about it.

Since I only had one pack, I did a starter – check out the krausen head:

Normally with dry yeast I would buy more packs instead of making a starter. I could only get one pack on special order with BRY-97, so I did a 1.5L starter. Due to the lag with this yeast (which I was not aware of at the time), it took 2-3 days longer than normal to finish out, and I had juggle my brew schedule.

Flocculation was great, the beer was clear after 2 weeks. No off flavors or any issues with esters or weirdness. The beer was quite drinkable after 30 days, so I take it this yeast doesn’t stay green as long. I’d use BRY-97 again for something along the lines of a Kolsch or summer beer, but not in a brew where I want the hops to shine.

This Home Brew Talk thread has pages and pages of interesting comments. There is a lot of concern about the lag time, extra price, and muted hops:

https://www.homebrewtalk.com/f163/anyone-try-bry-97-yet-333553/

Danstar’s product page is here:

https://www.danstaryeast.com/products/bry-97-american-west-coast-yeast

Post by Larry

Posted in Yeast Cultures | 3 Comments »

Unibroue Yeast – Available as Wyeast 3864 Belgian/Canadian Yeast

Currently on special release in Q4 of 2012, Wyeast 3864 Belgian/Canadian Yeast comes from a brewery called Unibroue in Canada, and has some distinctive Belgian like properties you might be interested in.

Discovering Unibroue:

Years before I began to homebrew, we took a trip to Canada. It was a wonderful experience, and a memorable trip. Part of the fun was trying Canadian beers we hadn’t seen before.

A few years after this trip, we were having lunch with friends. It was a relaxing early summer day, and we were eating outside. A beer sounded like a perfect idea (when isn’t it?) . I was looking at the beer menu, noticed a Canadian beer on the menu, and ordered it. Our trip to Canada had been in the summer and the weather was conjuring up those fond memories. That was when I tried a Unibroue beer for the first time – a glass of Blanche de Chambly.

One of the key moments in my craft brew early days was having that glass of Blanche de Chambly. It is a Witbier brewed by Unibroue, a Canadian brewery located near Montreal in Chambly, Quebec.

They specialize in Belgian brews exclusively. I began to seek out all the Unibroue beers I could find. All were full of character and delicious. I still adore their beers.

Brewing With The Unibroue Yeast:

Fast forward a few years and I began homebrewing. I find out that Wyeast is offering the Unibroue strain in their 4th quarter Private Collection. I snatch up a few smack packs and was off to the races. That was 3 years ago. It’s back this quarter. If you like Belgians and you like Unibroue beers, I’d encourage you to try the strain before it’s gone again!

Here’s a link the yeast strain information for Wyeast 3864.

I’ve brewed three beer styles with it: witbier, tripel, and a Maudite clone (the oft circulated Ky’s Maudite recipe). It ferments in a rather civilized fashion, and wasn’t a climber – even on the wheat beer. I will comment that the Maudite clone is NOT a “nailed” clone. It is a delicious Belgian Dark Strong beer, however.

Jamil Z’s Tripel recipe is a fine foil for this yeast. Fermented in the mid of the temperature range, it produced a lot of character but did take awhile to smooth out. This time I’m going to try the lower end this time and see if it will take less aging to round out.

Recipes that work well with the Unibroue Yeast (Wyeast 3864 Belgian/Canadian Yeast):

• Ky’s Maudite clone
• Jamil’s Tripel
• The witbier recipe I use – it is an adaption of an Austin Homebrew Supply recipe. I prefer adding oats in addition to wheat and pilsner.

Here’s a long cellared Ky’s Maudite in a glass. I had a few left in the back of my beer fridge. It is past its prime – the yeast strain character is fading – but it still tastes pretty good:

Unibroue Yeast Character:

I was thrilled to find that much of the “Unibroue character” is their proprietary yeast strain, and I was able to capture some of that essence in my batches. I’d describe the Unibroue strain as having a balanced and not overwhelming presentation of the typical hallmarks of Belgian yeasts: fruity character, spice, esters, and phenolics. At the high end of the fermentation range all these are amplified, especially the phenolics. I have found that if you overshoot the temperature range, aging can tame the flavors. This strain cellars well and retains it’s yeast character for 2 years or more if bottle conditioned and kept at cellar or refrigerator temperatures.

What I like best about the Unibroue strain is that it doesn’t hit you over the head with one particular note: it isn’t lots o’ spice, or lots ‘o fruit. It has these qualities present, but the flavor profile is not a “one trick pony” so to speak. There is also some acidity, which adds some focus and clarity to the Belgian character. Unibroue yeast is not as fruity as the Chimay strain (WLP500), not as spicy as the Achouffe strain (WLP550), and less civilized in character than the Westmalle strain (WLP530). In fact, some have speculated that Unibroue introduced some wild yeast from their Canadian region into a strain the founder brought over from Belgium.

To me the reason the strain is so delicious and also flexible is that it carries so many aspects of Belgian character – a complex flavor profile – but it does it in a refined and balanced manner. If you taste Blanche de Chambly (witbier), La Maudite (dark strong), and La Fin du Monde (tripel) side by side, you will easily detect the “Unibroue character” in each. However different each of these styles are, you will also find that yeast character appropriate and “at home” within that style’s profile.

This strain is very alcohol tolerant, and tastes good kegged or bottle conditioned. The highest gravity beer I’ve brewed with this strain thus far is about 9% – the Maudite clone, and I had no problems getting full carbonation in bottles with the original pitch.

I’ll add that Unibroue tends to carbonate their Tripels, Dark Strongs, etc. at the high end of the Belgian carbonation range. If you bottle condition, make sure you’re using strong bottles – most American bottles are suspect at holding those high carb levels and not becoming a bottle bomb.

I just purchased the equipment necessary for a frozen yeast bank so I won’t have to suffer the absence of this strain in off years. This is my favorite Belgian yeast, and I want to have it available!

If you like Belgians and you like Unibroue beers, I’d encourage you to try the strain. It is a very versatile Belgian strain and confers a strong but pleasant Belgian character in the beers I’ve brewed.

Posted in Beer Styles, Yeast Cultures | 5 Comments »

Yeast Pitch Rates Explained

To make high quality beer consistently, understanding your yeast pitching rate is important. In fact, this may be the key to taking your beer to the next level. It turns out that liquid yeast manufacturers give you barely enough to get by, which we explain in detail below. The yeast pitching rate describes how much yeast is going into the fermentor, per gravity unit. The standard rate is expressed as million cells / milliliter of wort / degree plato. Higher gravity beers and lagers call for a higher pitch rate. If the pitch rate is too low the yeast get stressed and produce undesirable byproducts, including soapy, chemical, and corn flavors (yuck!). Stressed yeast can even stall out, resulting in an incomplete fermentation (half way between beer and wort – not good).

Our yeast pitching calculator makes choosing and hitting your desired pitch rate very simple.

What is the impact of the yeast pitch rate on the beer?
A higher pitch rate leads to cleaner flavor profile because the yeast are reproducing less. A lower pitch rate can bring out more flavor from the yeast, but can also lead to inconsistency batch to batch.

What is the standard pitch rate?
A popular study done by George Fix concluded a rate of 0.75 million cells / ml / degree Plato is appropriate for ales, and double that for lagers. Other popular brewing tools use this number, though some opt for 1.0 instead of 0.75.

Lagers require about twice the pitch rate of ales, since they ferment at lower temperatures.

Pro brewers pitch at a higher rate to mitigate risk of infection, ferment quickly, and ensure a consistent product. Serious home brewers who want to get excellent beer pitch at higher rates too.

Our analysis indicates that at present, the liquid yeast manufacturers like White Labs and Wyeast give home brewers just barely enough yeast cells to get by for a typical batch of Ale. They say one pack or vial is enough for 5 gallons of wort at 1.060 and contains approximately 100 billion cells. This comes out to a pitch rate of 0.35 million cells per milliliter per degree plato. This is half the rate of what pro brewer’s use.

Why the low pitch rate from the manufacturers?
In their defense, the product does contain extremely healthy first generation yeast. One justification might be that the 0.75 rate really applies to pro brewers – who repitch. That re-pitched yeast contains some trub, dead yeast, and other junk, so the 0.75 rate is not as pure as the 0.35 manufacturer’s rate. Repithched yeast can’t be 50% gunk, probably closer to just 10% after washing.

To make matters worse with liquid yeast for home brewers, the overall viability drops as time passes. Liquid yeast viability drops 21% each month, or 0.7% each day, from the date of manufacture. So in about 5 months, that pack is pretty much dead. I only buy yeast manufactured in the last 4 weeks at my local home brew store, and I use it as soon as possible. Lesson here: only use the freshest liquid yeast, and get ready to learn how to make yeast starters if you want to use liquid yeast…

What pitch rate makes sense for the home brewer?

We asked a gold medal winning brewer and home brew store owner about this. He says he would never pitch at a rate of 0.35, and makes a starter for anything above 1.040 for a 5 gallon batch. We are convinced as well, though we realize making starters is not always an option for everybody. In our yeast pitch and starter calculator, we left it open so you can choose, or at least see what the manufacturers recommend vs the pros.

Overview of yeast pitching rates:

• New smack pack, MFG guideline: 0.35 (ale only)
• Middle of the road Pro Brewer 0.75 (ales below 1.060)
• Pro Brewer 1.00 (gravity above 1.060)
• Pro Brewer 1.50 (minimum for lager)
• Pro Brewer 2.0 (maximum, lager above 1.060)

Ways of achieving a higher yeast pitching rate:

A) Spend more money on fresh yeast (liquid or dry).

B) Make an appropriately sized starter – our yeast calculator handles that.  With dry yeast it is cost effective to buy more packs rather than make starters.

C) Re-pitch slurry from a previous batch. This should only be done under ideal circumstances (healthy fermentation, within 7-10 days, correct temperature range, beer below 6.5% ABV etc).

We have an introductory article on that subject here:
https://www.brewersfriend.com/2010/01/30/yeast-washing-101/

This Wyeast article has excellent and detailed on harvesting and re-pitching yeast:
https://www.wyeastlab.com/com-yeast-harvest.cfm

Ramblings on Yeast Pitching:

If a brewer tells you they pitched X number of yeast cells, that is just part of the story. What you really want to know is the pitch rate in million cells / milliliter of wort / degree Plato. Total yeast cells pitched only matters after you know the volume of the wort AND its gravity. Reason being – it takes more yeast to work through a higher gravity beer. You might also ask what generation the yeast were, what the slurry density was, and at what temperature the yeast were cultivated at.

Post by Larry

Other Brewer’s Friend Articles on the Subject:

We revisited our earlier articles on yeast starters and re-pitching to align with the information presented here:

• How To Make a Yeast Starter (OG 1.040)
• Stir Plates and Growing Brewing Yeast Quickly
• StirStarter Equipment Review

References:

• https://www.byo.com/component/resource/article/1749-yeast-pitching-rates-advance-homebrewing
• https://www.mrmalty.com/pitching.php
• https://www.wyeastlab.com/hb_pitchrates.cfm
• https://www.whitelabs.com/beer/homebrew_information.html
• https://www.calferm.org/edu/yeast/YEASTP.htm
• https://www.northernbrewer.com/documentation/YeastPitchingRates.pdf

Posted in Yeast Cultures | 2 Comments »

Infected Batch Forensics

For the first time in many years I experienced a bad batch of home brewed beer last month. I am sharing this with the community so you can avoid my mistake. It is embarrassing! Being out the time and money for the batch and having an empty keg sucks. However, I learned a couple things I can pass along. This bad batch changed my perspective on yeast re-pitching, updated my definition of what a healthy fermentation is, and helped me clean my equipment better.

The spoiled batch, which had been in the keg for about 2 weeks had the following properties:

• Initial flavor was anti-septic (almost burning).
• Murky appearance (different than chill haze).
• Slippery mouth feel.
• Finshed soapy, with the flavor getting more pronounce, to the point I spit it out. The bitter antiseptic flavor lingers on the tongue.

What the heck! Had I gotten a lax on sanitization? Was my yeast bad? Was there something in the brewing process that lead to this? I asked some home brewing experts and they attribute this to a yeast deficiency – either an infection, or bad yeast. It turns out there were two main factors, repitching of yeast and a dirty spigot in my fermentor. While I am not sure which did more damage, I have evidence of both.

Here is what the carboy looked like, note the ring:

If you have a goopy ring around the krausen layer you might be in trouble. The off gases from the fermentation also smelled ‘cheesy’, which tipped me off there might be a serious problem.

Beer Forensics:

For what turned out to be the spoiled batch, I opted to re-pitch yeast (Wyeast Northwest Ale 1332) from a previous batch of IPA. The harvested yeast was in the fridge in a ball jar for about 2 weeks. That IPA was already in the keg and was drinkable, but it was not my best batch ever. It had a thin finish and there were some light ‘chemical’ flavors present that come and go from sip to sip. I figured at the time, the beer was just green – and it did improve a lot after a month went by. When I kegged the IPA and harvested the yeast, it looked and smelled fine, a fresh bready aroma was present. That meant it is good to go right? WRONG!

Something funny happened with the fermentation of that IPA. One night I forgot to set the furance at 64F, and instead turned it all the way down to 58F – so it got pretty cold in the house that night. It turns out NW Ale 1332 does best between 65F and 75F. In effect, that night the yeast were really stressed. I didn’t think much of it at the time. I do recall the fermentation slowed after that. I also left the IPA in the primary for 23 days, without racking, and then harvested the 23 day old yeast cake. In retrospect I should have spent the $4-$7 for a new yeast pack. Even though that yeast cake smelled good at the time, it was no longer to be trusted given its age, and the temperature fluctuation.

I gathered two ball jars from the yeast cake. Now a month later, on inspecting the second ball jar, there is a thin line of black mold growing on top. YUCK!

That IPA was fermented in a plastic bucket with a spigot. The subsequent failed batch was fermented in a glass carboy. I went ahead and tore apart the spigot on the bottling bucket, and look what I found in there:

It had probably been over 3 years since I setup that bottling bucket and spiot. Whoops! No doubt whatever mildew / mold / germ was living in there is not good for the beer. I terminated it with extreme prejudice – a strong bleach solution!

After I soaked everything, I thought I was ready to go again, but then I noticed, inside the sealed part of the spigot, there were some faint black spots. It is hard to see in the picture, so I enhanced the second one.

The mold / mildew, whatever it is, is growing INSIDE the sealed part where the spigot rotates. There is no way to scrub that section. I am looking into getting a different type of spigot that does not have this design flaw.

Yeast Re-pitching Revisited:

All this time I had thought I was being a good sport by re-pitching yeast. That is what the pro’s do right? Well, it turns out I did not realize the risks associated. I wrote an article awhile ago that praises yeast washing, and another on yeast repitching. I have updated those articles to point out what was learned here. The time it takes to harvest and clean the yeast (15-20 minutes), plus the risk is not worth the $3 savings it offers! I should have known that…

Key Take Aways:

• Yeast re-pitching can be risky and might not be worth the cost savings for home brewers.
• If you are going to repitch – I would rack after about a week and save that yeast. Let the secondary fermentation finish on its own, and discard that smaller, older yeast cake. I would also be very strict about temperatures ranges and sanitization. I successfully repitched many many times, but now I am starting to see where perhaps some inconsistency came into play.
• Tear everything apart now and then and completely clean it with PBW or a bleach solution if the materials are compatible with bleach.
• Look for stuff growing inside what appear to be sealed parts, such as the spigot on the bottling bucket.

PROST!

Posted in Brewing, Yeast Cultures | 9 Comments »

Pacman Yeast – Eureka!

Pacman is the name of the yeast used by Rogue Brewery of Oregon. Rogue makes Pacman available in limited quantities to home brewers from time to time.

Originally, I didn’t get the name. Were they being cute? Does it ‘pack’ a punch? No, I was not thinking literally enough. While on vacation it dawned on me. The name was inspired from the old arcade game! It helped that weeks before my vacation I had played the Pacman game on Google (https://www.google.com/pacman/). What Pacman does in the game, and what brewer’s yeast does in the wort are pretty similar.

To help us all remember, I created a somewhat crude and juvenile drawing. This makes for a basic lesson in ‘God Is Good’, aka yeast, and how they turn sugar into alcohol:

Our big hungry yellow hero ‘Pacman’ is a yeast cell (technically a fungus). Him, and thousands of his brothers and sisters eat their way through sugar molecules in sweet wort. As they consume the sugar they produce alcohol, carbon dioxide, and some sulfur dioxide. Yes, alcohol is fungus crap. Poetic. The SO2 is why if you take a sniff from the airlock it can smell a little funny. This varies by yeast strain. Normally I smell hop aroma from my airlock, but I have smelled ripe odors from Hefe and Kolsch strains in particular.

There are some oversimplifications here. Yeast need oxygen to do well. That’s why it is important to aerate! Yeast also utilize minerals and other compounds present in the wort. As the yeast eat, they reproduce faster than rabbits. Healthy fermentation is like a wild orgy on a microscopic level.

When the party is over there will still be some sugars remaining. Some brews, like dry mead, use a yeast strain that goes all the way to a final gravity near 1.000 (no sugar left). Each yeast strain has a different alcohol tolerance and capacity for digesting complex sugars. The yeast eat themselves into an environment they cannot survive in. That’s okay though, they can be harvested off the bottom and saved for another batch or immediately repitched if all was well with the fermentation.

Posted in Yeast Cultures | 1 Comment »

Yeast Washing 101

Yeast washing is a simple, yet useful procedure that will allow you to harvest, store, and re-use yeast from your own yeast bank for pennies per brew session. Please review how to make a starter and why a stir plate to help you best re-activate your yeast after cold storage.

SANITATION: You must sanitize everything in this process! Storing yeast successfully is fully dependent on keeping the samples pure.

YEAST STOCK: You will harvest the yeast that you are about to wash and store from a recently (same day) emptied fermenter. This yeast cake or slurry will be the basis for all that you are about to do. This is the yeast that will go on to propagate new colonies in future brews. See Fig 1

Fig 1.

HARVESTING: After racking the fermented beer from atop a yeast cake, there will generally be some liquid left along with the yeast cake. Swirl this around and loosen the yeast cake so that you can pour the slurry (sometimes chunks) of yeast into a sanitized flask or 1 gal. carboy. You want plenty of spare volume. Your yeast slurry will be full of trub, some break material, and hop particles. Currently, it is probably looking VERY thick and has no defined layers, though we are about to fix this! Fig 2

Fig 2.

WASH: You will want to have about a half gallon (ample amounts) of boiled and cooled water on hand (so we don’t cook the yeast). In your flask or carboy use enough of this water to double or triple the volume of the slurry that you currently have. Give it a few swirls to mix all of the contents (slurry and water) together. Cover with sanitized foil. See Fig 3

Fig 3.

WAIT: Given as little as 15-20 minutes to sit, you will be able to see some drastic stratification in your slurry. The heavier particles, trub, and break material will settle out quite quickly, leaving a dark layer with progressively lighter layers above it. Atop these dark layers you will have a creamy layer of liquid. This is what you want, water and yeast in suspension. See Fig 4

Fig 4.

SEPARATION: You will want to have several sanitized jars available to decant this creamy, yeast filled liquid into. Pour the creamy liquid containing the suspended yeast off of the sediment and into as many jars as it takes to hold it. Now you will have 2-4 jars full of this creamy looking liquid that you will place sanitized lids on, and then place into the refrigerator. See Fig 5. After some time has passed in the fridge you will see that the liquid is now much clearer and there is a nice bright layer of clean yeast at the bottom of each jar. See  Fig 6

Fig 5.

Fig 6.

STORING: If your sanitation practices are good, you can store this yeast for months. The yeast should remain in these jars, sealed and refrigerated, until you are ready to make a yeast starter to awaken them. It would also be a good idea to mark these jars with the yeast name, the date, and R1, for “reuse #1”, This way you can keep track of how many times you have re-used this yeast. See Fig 7. Typically after repeated uses the yeast will begin to mutate and its characteristics may change to a degree. You can typically feel confident re-using yeast 4-5 times before degradation is detected.

Fig 7.

RE-USING: When you would like to re-use this strain of yeast, simply allow a single jar of washed yeast to gradually warm to room temperature, decant the liquid and pitch the washed slurry from the bottom of the jar into some new starter wort. See how to make a yeast starter HERE.

IMPORTANT NOTES:

1. You can NEVER be too careful with sanitation when it comes to yeast washing/storing.
2. Do use a large clear glass container (large flask or 1 gal. carboy) for the HARVESTING and WASH steps in the process.
3. Ball or Mason jars make excellent containers for the WAIT and STORAGE steps in the process.
4. Be sure to sanitize the jar lids before securing them and storing your yeast.
5. Mark your jars with the yeast name, the date and the reuse/generation number (R1, R2,…) and so on to keep track of how many times you have washed this yeast and re-used it.

Update 11/12/2011: Check out the article on Bad Batches to see why you might want to avoid re-pitching yeast, or if you do so, make sure to understand the risks involved.

Posted in Yeast Cultures | 32 Comments »

StirStarter Equipment Review

An essential tool in the home brewer’s kit is a stir plate. Using a stir plate with a yeast starter boosts yeast cell counts dramatically*. This leads to healthier fermentation, and thus better beer! I recall using a stir plate in chemistry lab. In that case it was a hot plate and stir plate combined. When I looked these up online, I found they were quite expensive (excess of $100).  Thankfully the StirStarter exists and fills this need for brewers perfectly at a much more affordable price. https://www.stirstarters.com/.

The stir starter comes complete with everything you need. It measures 4”x6” which is fine for up to a 1 gallon vessel. Any Erlenmeyer flask for yeast starters would fit comfortably on StirStarter.

It includes a rubber mat for the top so the flask grips the surface nicely.

Stir bar, catch magnet, instructions, and power supply (not pictured) are also included.

Using the StirStarter is simple. A yeast starter is prepared as normal. A sanitized magnetic stir bar is dropped into the flask containing the yeast starter. The stir bar is then centered in the bottom of the flask with a catch magnet (kept on hand). The flask is then set down on top of the stir plate. Gently the spin speed is increased to a steady rate. A whirlpool effect is not needed. If the dial is set too high the magnet can get spun off center. The spinning stir bar continuously mixes the contents of the flask. This increases the surface area potential of the yeast, leading to more yeast activity.

Some other notes about Dan at StirStarter. He ships fast, my package got here within three days. There is also a lifetime guarantee on the product. That is hard to beat.

In case you are thinking about building one yourself, here is the inside of the unit:

There are a few things going on in there involving electronics that have to be correct. One is the power level for the fan, the other is the wiring for the speed switch. The StirStarter website provides instructions on how to build your own. After just a couple seconds of reading, I realized building my own would be trouble. It would take me several trips to the electronics store and the better part of a weekend to build my own.  At the low price of the StirStarter, there is not much savings potential over buying a StirStarter worry fee built by a pro.

This site will feature an upcoming article about yeast washing, which explains saving and recycling yeast over and over again.

* According to MB Raines’ article about yeast starters, stirred yeast starters can get as much as ten times the amount of active yeast compared to a standard shaken yeast starter. According to the brewersfriend.com article on stir plates, it may be closer to a 100% increase.

StirStarter was kind enough to hook me up with a StirStarter for writing this post.

Posted in Equipment, Yeast Cultures | 5 Comments »

Yest Review SafLager W-34/70 Dry

An excellent property of dry brewing yeast is that they have a very high cell count, they store well (years) and the yeast are packed with nutrient reserves which allow for fast starts. When brewing lagers, the vast majority of yeast strains are liquid yeast strains, requiring large starters for lager beers. Liquid yeasts contain a much lower cell count and lack the nutrient reserves that the dried yeast strains hold. For this reason it is nice that there are a few dried lager yeasts available to home brewers. Here is a review of Saflager W-34/70, a very popular (worldwide) German lager yeast strain.

• Starter recommended?: YES and NO **see commentary below.
• Starter size (for 5 gallons): 3L
• Starter OG: 1.040 – 1.050
• Starter incubation time: 24-48 hours
• Blow off recommended?: NO
• Optimum fermentation temperature: 48F-59F
• Suggested ambient air temp during first 24 hours of fermentation: 53F
• Suggested ambient air temperature after 24 hours of fermentation: 53F
• Scent during fermentation: Sulfur
• Flavor profile: Very malty and clean, great for German lagers and pilsners, low diacetyl
• Flocculation: Medium
• Attenuation: 73%-77%

**Being that W-34/70 is a dry lager yeast, a yeast starter is not necessary under one condition… you pitch enough of the re hydrated dry yeast to properly inoculate the wort.  www.MrMalty.com contains a yeast pitching calculator which will guide you as to how much dry yeast you will have to pitch in your lager.

**A lager with an OG of approximately 1.050 will require (2) 11g dry yeast packets, OR a 3 liter starter. In this case I would prefer to pitch (2) packets of re hydrated yeast and forgo the starter, here is why. The dried yeast is ready to ferment, it is packed with nutrients, and while using (2) packets you will meet or slightly exceed the required yeast count for your wort. Even a 3 liter yeast starter, though still meeting the required yeast count for your wort, will have burned up much of the stored nutrient reserves that were in the dry yeast prior to creating the starter.

Pitching the re hydrated dry yeast will give you a faster start for this reason. Two packets of W-34/70 will cost you about $6.00, . If you prefer to create a starter while using W-34/70, see how to make a yeast starter at brewersfriend.com.

When pitching lager yeasts, there are two methods by which to do it, pitching warm or pitching cold. A warm pitch will take place at a temperature of 65-70F, then the temperature is slowly lowered to the ideal fermentation temperature of 48-59F. This is done by some brewers to accelerate the start of the fermentation and lessen the lag time, it will also require a slightly lower pitching rate for these reasons.  There are concerns however of off flavors being produced from the limited time at warm temperatures, but the yeast can clean this up with a diacetyl rest after primary fermentation.

Pitching cold is simply the process of pitching yeast at fermentation temperatures ranging from 48-59F. This will result in a slightly longer lag time and require a healthier yeast count to get fermentation started in a timely manner. This is preferred however by many lager brewers to avoid any possibility of off flavors that can be created during a warm pitch.

Considering the high quality of this yeast strain, the ease of use as a dry yeast and its popularity in brewing circles around the world, it is a must try both for the novice and advanced lager brewer. Buy (2) packets, rehydrate them and pitch straight into your wort.

The beer turned out very clean, slightly malty, it was a great example of a German Pils. I am enjoying it thoroughly after about 2 months of lagering. Enjoy!

Posted in Yeast Cultures | 1 Comment »

Stir Plates and Growing Brewing Yeast Quickly

Creating a simple yeast starter as outlined here at brewersfriend.com will greatly increase your yeast cell count, but there is a way to easily supercharge this process. By using a stir plate you will be able to grow nearly 100% more yeast cells using the same volume of starter in the same amount of time. Basically, for the same investment in yeast, time and starter liquid, you will be able to double your yeast production with a stir plate.

A stir plate is a simple machine consisting of a base which houses a motor with variable speed control. Fig 1. This motor is used to spin two precisely spaced magnets, which in turn will spin a magnetic stir bar inside your flask. The intent here is to use this stirring motion to:

1. Keep the yeast in suspension
2. Release CO2 from the starter solution
3. Continuously aerate the starter liquid

Fig 1.

There are several important guidelines to follow when utilizing a stir plate to create a starter:

1. Ideally, boil the starter wort in the flask that you will be using to create the starter, this will help to sanitize the flask.
2. DO NOT use an airlock on a stir plate starter as it will impede the ability of the stir plate to exchange CO2 from the fermentation for O2, which will help grow yeast.
3. DO use foil to cover the top of the flask instead of an airlock.
4. Ferment the starter at 75F – 80F. While not optimal for flavor production, you are trying to grow yeast, and warmer temperatures will accelerate this process.

By doing the above, you are creating the perfect growing environment for your yeast cells, allowing them to grow at a much greater rate than they would with the use of a simple starter with no stir plate. After the starter has fermented out completely (approx 24 hours), remove the starter from the stir plate and chill so that the yeast may settle. After a short period of time (several hours), the yeast will form a nice thick slurry in the bottom of the flask, allowing you decant the starter wort prior to pitching. Decanting is required since the wort has been oxidized and fermented at a higher temperature than is optimal for most yeasts (75F-80F recommended). Though this temperature is excellent for yeast growth, it does not leave a very favorable flavor in the starter liquid.

Our yeast pitching calculator makes choosing and hitting your desired pitch rate very simple.

Our calculator will allow you to enter all of the vital statistics about your wort so that it can properly calculate the number of yeast cells you will require, the required volume of your starter wort and the volume of yeast slurry that you must pitch to meet your ideal pitching rate.

Below is a side by side comparison of the number of yeast cells created in a 1.5L simple starter (no stir plate) and a 1.5L stir plate starter. The results may surprise you!

Starter volume: 1.5L
Amount of Yeast used in starter: (1) Liquid Smack Pack / Vial – 100B cells
Fermentation Time: 24 hours
Temperature: 75F (recommended to quickly grow yeast)

Using the above criteria, a simple starter will produce approximately:

182 billion yeast cells, pitch rate of 0.71 M cells / mL / °Plato (just below the pro recommended pitch rate)

Using the above criteria, a stir plate starter will produce approximately:

282 billion yeast cells, pitch rate of 1.09 M cells / mL / °Plato (a very healthy pitch rate)

As you can see from the above comparison, utilizing a stir plate you are able to increase by 100% the yeast growth with the same amount of starter wort while using the same amount of yeast pitched into said starter. Conversely, you can also create the same amount of yeast in a stir plate starter as you are able to with a simple starter, with nearly half the starter volume. The latter is of great interest to lager brewers who will routinely need to create very large starters to reach the proper pitching rate for their lager beers. Lagers will routinely require a 3L-4L stir plate starter. If you utilized a simple starter (no stir plate), you would be in the neighborhood of 6L to reach the proper pitching rate.

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