[hopshead]

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.

[S. cerevisiae]

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

[hopshead]

Ahh, well that makes sense.  Time to experiment with "true" top croppers.  Thanks for the help.

[S. cerevisiae]

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. 

[hopshead]

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?

[hopfenundmalz]

WLP-022 is also a top cropper.

[joe_feist]

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.

[S. cerevisiae]

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

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.

[69franx]

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

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.

[S. cerevisiae]

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.

[coolman26]

Great information, I've learn more on this forum than all others I've frequented. 

[joe_feist]

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.

[S. cerevisiae]

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.

[macbrews]

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

[S. cerevisiae]

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.