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General Category => Yeast and Fermentation => Topic started by: hopshead on February 18, 2015, 08:18:54 PM

Title: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: hopshead on February 18, 2015, 08:18:54 PM
Brief Brewing Background
I have been homebrewing for 9 years (8 of that all grain).  I brew 24-26 times a year (every other weekend) and I usually make 5-6 gallon batches.  For the last 3 years I have been top cropping ale yeast with various different procedures.

Top Cropping Procedures
My current top cropping method isn't very technical and I recently lost a batch of beer so I want to hear from the yeast wizards out there if there is anything they would change.

Typically 48 hours after pitching my yeast, I use a sanitized (starsan) measuring cup and lift the lid of my brewbucket and carefully scoop the yeast on top of the beer and put it in a re-purposed 8 pound size PBW plastic jug (sanitized with starsan).  I always put the plastic jug on a scale (set to measure grams) and I try to collect 100 grams of the foam from the beer, but sometimes I fall short because I pulled all of the foam already.  Then, I sanitize the valve on the brewbucket and pour in about a pint of beer on top of the yeast I collected.  The lid to the plastic jug is fitted with an air lock and I screw this on and let the beer ferment in the small jug for 2 days, then refrigerate.   About 1-3 days in advance of a brew day, I make a 1 quart starter and pour this into the jug and to wake the yeast up and have some (although who knows how much) cell growth.

Now to the beer I lost... I had been top cropping WLP001 since July 2014 and the 15th batch went bad.  All previous batches of beer were good, but I did notice a house flavor developing.  I am not sure if I had bad cleaning and sanitation that led to the bad batch or I slowly picked more contaminates in the yeast that finally took over the pitch.  At any rate, I think going that many generations might be to many so I will start buying a new pitch sooner.

Let me know if you have any questions and thanks in advance for any advice you may have.
Title: Re: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: S. cerevisiae on February 18, 2015, 08:44:16 PM
The problem is that you are attempting to top crop a non-true top-cropping strain.  Yes, there are a few yeast cells in the krausen, but that's not true top-cropping.  True top-croppers produce a thick yeast head on top of the beer, not just foam.

Here's a partial list of easily obtainable true top-cropping strains:

Wyeast 1007
Wyeast 1318
Wyeast 1335
Wyeast 2565
Wyeast 3068
Wyeast 3638
Wyeast 3787
Wyeast 3944

Title: Re: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: hopshead on February 18, 2015, 09:00:43 PM
Ahh, well that makes sense.  Time to experiment with "true" top croppers.  Thanks for the help.
Title: Re: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: S. cerevisiae on February 18, 2015, 11:24:49 PM
One thing that I forgot to mention is that you need to skim and discard the first head when using a true top-copper.  That head is referred to as the "brown head" by British Brewers.  The second head that forms after the brown head is skimmed is cropped for re-pitching. 
Title: Re: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: hopshead on February 19, 2015, 12:50:56 AM
I remember seeing something about the braun hefe.  I guess I will skim and discard at 24 hours and skim for repitching at 48.  I am making a starter now with WLP022 (essex).  They say that is a top cropper.  Anyone have experience top cropping this strain?
Title: Re: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: hopfenundmalz on February 19, 2015, 01:04:44 AM
WLP-022 is also a top cropper.
Title: Re: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: joe_feist on February 19, 2015, 05:14:36 PM
I'll start by saying I don't top crop, but have been wanting to, so I'm paying attention and asking.
First, maybe WLP001 isn't a true top crop yeast, but he did get 14 good batches. Could it be he went too far on the number of generations? I've heard/read that 10 or 12 generations is about as good as it gets.

Second question, other than the specific yeast what do you guys think of the process? Again, it's something I want to try so I'm curious.
Title: Re: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: S. cerevisiae on February 19, 2015, 05:56:54 PM
I'll start by saying I don't top crop, but have been wanting to, so I'm paying attention and asking.
First, maybe WLP001 isn't a true top crop yeast, but he did get 14 good batches. Could it be he went too far on the number of generations? I've heard/read that 10 or 12 generations is about as good as it gets.

As I mentioned above, there are a few yeast cells in a foam krausen, but the cell count is much lower than it is in a yeast head. The low cell count is why the OP is picking up a house flavor.  That flavor is the result of house flora contamination being able to compete with the domesticated pitching strain.  Twelve generations is good when bottom cropping, but it is not even remotely close to being good when top cropping a true top-cropper.  For example, most of the Peter Austin designed breweries that were built by Alan Puglsey repitch Ringwood (WLP005) for hundreds if not thousands of generations. Harvey's in the UK has been repitching the same top-cropping yeast culture for over 50 years. 

The difference between a foam head and a true yeast head is that a true yeast head is almost pure domesticated yeast.  True top-croppers rise to the surface as fermentation nears terminal gravity.


This article gives a good overview of  true top-croppers: http://hbd.org/uchima/yeastzone/topcrop.html

Quote
Second question, other than the specific yeast what do you guys think of the process? Again, it's something I want to try so I'm curious.

Top-cropping works best with open fermentation, but it will work with any container that has a removable lid. With the right yeast strain, top-cropping can basically give a brewer who brews on a regular basis a limitless supply of yeast.
Title: Re: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: 69franx on February 20, 2015, 04:28:22 AM
I'll start by saying I don't top crop, but have been wanting to, so I'm paying attention and asking.
First, maybe WLP001 isn't a true top crop yeast, but he did get 14 good batches. Could it be he went too far on the number of generations? I've heard/read that 10 or 12 generations is about as good as it gets.

As I mentioned above, there are a few yeast cells in a foam krausen, but the cell count is much lower than it is in a yeast head. The low cell count is why the OP is picking up a house flavor.  That flavor is the result of house flora contamination being able to compete with the domesticated pitching strain.  Twelve generations is good when bottom cropping, but it is not even remotely close to being good when top cropping a true top-cropper.  For example, most of the Peter Austin designed breweries that were built by Alan Puglsey repitch Ringwood (WLP005) for hundreds if not thousands of generations. Harvey's in the UK has been repitching the same top-cropping yeast culture for over 50 years. 

The difference between a foam head and a true yeast head is that a true yeast head is almost pure domesticated yeast.  True top-croppers rise to the surface as fermentation nears terminal gravity.


This article gives a good overview of  true top-croppers: http://hbd.org/uchima/yeastzone/topcrop.html

Quote
Second question, other than the specific yeast what do you guys think of the process? Again, it's something I want to try so I'm curious.

Top-cropping works best with open fermentation, but it will work with any container that has a removable lid. With the right yeast strain, top-cropping can basically give a brewer who brews on a regular basis a limitless supply of yeast.
So my follow up revolves around time frames. You say top cropping works best at or towards the end of fermentation, but the OP is talking about skimming the Braun hefe at 24 hours and top cropping   at 48 hours. Doesn't seem like the time frames match up well, but does it work at this point for him if using  a true top cropping strain? I think that's the kind of question everyone is really thinking about. Any info you have helps me, as I have not done any top cropping for any of my batches, really just trying to understand good process steps here.
Title: Re: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: S. cerevisiae on February 20, 2015, 01:06:35 PM
Most true top-croppers are capable of taking a beer down to terminal gravity within three to four days if fermented at normal ale fermentation temperature instead the modern American home brewing practice of fermenting ale near the top-end of the lager range.

Traditional British breweries skim and discard the brown head at around 24 hours into the fermentation because it contains hop polyphenols that give beer a harsh edge.  British breweries skim several times during the fermentation.  The yeast that one wants to keep occurs after the brown head is skimmed.  It's the top cropping equivalent of selecting the middle layer from a conical.

Wyeast 1469 can be seen in its native environment in the linked video in the "Fermentation and Maturation" section of this page: http://timothytaylor.co.uk/brewery

That's how a Wyeast 1469 fermentation is supposed to be handled.  Rousing and aeration during the second day of fermentation is a traditional practice with Yorkshire yeast strains.  Ringwood is also a Yorkshire yeast strain. All Peter Austin designed breweries have one of those shower head looking yeast rousing and aeration devices (So does Harvey's of Sussex).  This video and others kind of blow a hole in the argument that racking to a secondary at the end of primary fermentation will oxidize one's beer.   As I have mentioned many times, the yeast cells that are in suspension will rapidly scrub any O2 that is introduced during racking; hence, the reason to rack or not to rack should be based on something other than the threat of oxidation.

Title: Re: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: coolman26 on February 20, 2015, 02:13:26 PM
Great information, I've learn more on this forum than all others I've frequented. 
Title: Re: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: joe_feist on February 23, 2015, 05:34:35 PM
Thanks for clarifying the process. The videos are fun and very helpful, too. I've played around with open fermentation with a 20 gallon ceramic vat my wife picked up somewhere. I think I'll add  top cropping to the process and see how that goes.

I held the open fermenter in a fridge at 61 degrees ambient. I may go a tad cooler next time; specific yeast dependent.
Title: Re: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: S. cerevisiae on February 23, 2015, 06:29:01 PM
Other then Wyeast 1007/1010, most true top-croppers prefer 68F to 60F.  With respect to internal heat, fermentation vessel height makes a difference in open fermentation.
Title: Re: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: macbrews on February 24, 2015, 03:22:29 AM
Let me pose another question to this thread:

I often brew hefes with Wyeast 3068.  Due to the often near-violent fermentation of these and the ensuing mess, I have given up on using the regular air locks and just use blow-off tubes which go to a container that I fill with starsan.  There is always a LOT of yeast in the bottom of the blow-off container.  I have never considered using it because of the starsan.  If I were to run the blow-off tube to a sanitized container filled with sterile, treated tap water, or for that matter a cheap lower-gravity beer, would that be a reasonable way to harvest the yeast? 

I use Better Bottles to ferment in, so top cropping as described above is not an option for me.

Thanks,

Mac
Title: Re: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: S. cerevisiae on February 24, 2015, 02:29:52 PM
First off, boiled water is not sterile.  Boiling only kills vegetative cells.  It does not kill spores.  Water has to be raised to 121C/250F at 15 pounds per square inch above normal atmospheric pressure in order to render it absolutely sterile.  The pH of boiled water is also not ideal for the storage of yeast.

With that said, Wyeast 3068 (a.k.a. Weihenstephan W-68) is an open fermentation vessel yeast strain (that's how the strain was selected).  Ideally, you want to use a rivet-free stainless steel or plastic fermentation vessel that is large enough to contain the yeast head between skimming.
Title: Re: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: Stevie on February 24, 2015, 02:40:35 PM
You could try making a Burton Union type device.

http://byo.com/hops/item/351-build-a-burton-union-system-projects
Title: Re: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: macbrews on February 24, 2015, 05:15:53 PM
You could try making a Burton Union type device.

http://byo.com/hops/item/351-build-a-burton-union-system-projects

That is an interesting set up that looks easy to make.  My original thought was to not have the spillage return to the fermenter, but having the original wort in the container rather than something else makes a lot of sense.

Thanks,

Mac
Title: Re: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: chris.davinroy on March 06, 2015, 06:43:22 PM
So, what is the ideal pH of water to store yeast. I am just getting into harvesting for a YEAST that I will be using 4~5 times per year. I've watched video upon video about harvesting and no one mentions this. I just quickly browsed the section on this i the book entitled "Yeast" (one of the 4 part series entitled Yeast, Water, Malt, Hops) and they didn't mention it in that 'section'. Again, I didn't go into great depth in the book, so I am sure that it is referenced in there somewhere.
Title: Re: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: denny on March 06, 2015, 07:12:40 PM
So, what is the ideal pH of water to store yeast. I am just getting into harvesting for a YEAST that I will be using 4~5 times per year. I've watched video upon video about harvesting and no one mentions this. I just quickly browsed the section on this i the book entitled "Yeast" (one of the 4 part series entitled Yeast, Water, Malt, Hops) and they didn't mention it in that 'section'. Again, I didn't go into great depth in the book, so I am sure that it is referenced in there somewhere.

The real answer is that it doesn't matter becasue you shouldn't store yeast under water.
Title: Re: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: chris.davinroy on March 06, 2015, 07:36:42 PM
Denny, in the book I mentioned, the tell you under water is safer than under beer. Again, I have no experience in this and I am looking for guidance.
Title: Re: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: denny on March 06, 2015, 07:40:58 PM
Denny, in the book I mentioned, the tell you under water is safer than under beer. Again, I have no experience in this and I am looking for guidance.

All I can tell you is that I and a lot of other people disagree with that advice.  I'm basing my opinion on my experience of trying it both ways.  There is a very experienced yeast guy on the forum who goes by S. Cerviseae.  Although we disagree on some things, I'm firmly in his camp when he says storing it under beer is better.  But I encourage you to try both and decide for yourself.
Title: Re: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: chris.davinroy on March 06, 2015, 07:43:09 PM
Cool, Thanks for the tip. Always learning.
Title: Re: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: denny on March 06, 2015, 07:44:41 PM
Cool, Thanks for the tip. Always learning.

This is one of those hobbies where you never stop learning.
Title: Re: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: S. cerevisiae on March 08, 2015, 05:20:25 PM
Denny, in the book I mentioned, the tell you under water is safer than under beer. Again, I have no experience in this and I am looking for guidance.

The practice outlined on page 168 of Yeast goes against what is practiced by the professional brewing community and most of the long-time veterans in the amateur brewing community.  In fact, the practice contradicts what Chris White wrote for BrewPub magazine, which leads to me to believe that the yeast rinsing section was a Jamil addition. 

http://www.probrewer.com/library/archives/keeping-your-yeast-healthy-longer/

Quote
Yeast is a living organism and is most happy and healthy when feeding on wort sugars. When fermentation is complete, yeast cells flocculate to the bottom of the fermenter. They then go into a resting state. Yeast under beer is fairly stable, and most brewers agree that the best place to store yeast is under beer. But two crucial factors are temperature and time.

The problem with the yeast rinsing section of the book is that many home brewers have misinterpreted what was written.  The authors offered the technique as a method to select yeast cells.  Here's the first paragraph from that section:

Quote
The question many homebrewers have is, "How do I select only the best yeast if harvesting the entire contents of the fermentor?"   The answer lies in yeast rinsing.  While it cannot replace selecting the ideal yeast with a shovel, it can help separate out the trub, dead cells, and alcohol from your pitch.

There are other ways to select the best cells that do not involve the possibility of contaminating one's culture.  I outlined a process that many amateur brewers use to bottom crop relatively trub and dead cell free yeast without exposing the culture to boiled water in the thread linked in my signature.

The authors go onto attempt to justify a risk-laden process in commercial settings.

Quote
Rinsing can also be worthwhile in commercial settings, especially for yeast harvested from a high-gravity beer.

Green beer, while toxic to domesticated yeast, is even more toxic to house microflora.  Green beer also contains non-fully digested sources of carbon.  Sugar belongs to a class of substances known as carbohydrates.  Carbohydrates are compounds made of carbon bound to water (i.e., hydrated carbon).  All the sugars found in wort break down into multiples of CH2O.  The simplest sugars found in wort are known as hexoses because they contain six carbon atoms.  The most common hexose is glucose.  Hexoses have the chemical formula C6H12O6.  Ethanol is also source of carbon. It has the chemical formula C2H6O (or CH3CH2OH).  Under the right conditions, yeast will consume ethanol via a metabolic process known as diauxic shift.

Finally, here's something that Fermentis wrote about storing yeast out of beer:

http://www.fermentis.com/wp-content/uploads/2010/07/2010_TT_EN_HD.pdf

Quote
In case of repitching, yeast must not be stored out of beer for long periods, even at low temperatures, as yeast
glycogen levels will fall causing slow fermentations.

Fementis' parent company, Lesaffre, is a multi-national yeast and fermentation powerhouse.   Their yeast research spans brewing to yeast lines used in health-related research.  If you perform a Google search using the terms "Lesaffre" and "bioreactor," you will see that Fermentis is just a drop in the Lesaffre yeast bucket.
Title: Re: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: chris.davinroy on March 08, 2015, 05:41:32 PM
S.cerevisiae, thank you for the tips. I will read them carefully and store them in my favorites. This one will probably not survive as I had 1/4 inch of creaminess on the bottom of my secondary. Now I barely have a 1/16 of an inch in my pint jars.

Thank you, again, for hekping this to be a better environment. Beer people rule!
Title: Re: Yeast Wizards - Please critique my Top Cropping Procedures
Post by: hopshead on March 16, 2015, 06:22:46 PM
WLP-022 is also a top cropper.

I just top cropped the Essex Ale for a second time this weekend.  It is EXTREMELY different looking than the Cal Ale I was using.  Very dense and I easily collected 80 grams of yeast.  After collecting the yeast, several hours later, a new krausen formed and could have been cropped again if I wanted. 

Based on S. Cervevisiae posts in this thread, I may be top cropping too soon however.  In this second harvest, I skimmed the braun hefe and discarded around 16 hours after pitching.  The actual harvest was about 24-26 hours after pitching.  It may take me a while working with this yeast to figure out the "right" time.  But so far I have been impressed.

I also agree with storing yeast under fermented beer, not water.  A couple of years ago I was storing under water (still harvesting Cal ale at the time), I lost batches of beer due to spoiled yeast very quickly (4-5 generations). 

I brew every other week, so in my process, I collect some wort from the fermenter (through the valve of the SS Brewtech bucket) to let the top crop ferment (about 2-3 days), then I store in my kegerator for about 7-8 days, then make a quart to 2 quart starter for the yeast to feed on a couple of days before the next brewday.

Before fermenting in the bucket, I was top cropping from a carboy.  Get an orange carboy cap and insert a racking through it so the end sticks into the krausen.  This is basically a forced blowoff.  It works, but it takes longer to collect.

cheers!