Top cropping vs. post fermentation harvest

roddy · February 6, 2012, 11:52pm

Is there a difference in yeast quality with these two methods? I recently started making 10 gallon batch in plastic containers and now would have easy access to top cropping.
In the past when I harvested from my carboy, I could get close to two mason jars full of yeast. I am guessing I would not get near this quantity from top cropping (or would I)?
My understanding of top cropping is to harvest the kruesen using a spoon.
Is the kruesen then placed in a starter to make more yeast, or is it placed in a mason jar in the same way yeast is poured into the jar after fermentation?

Does top cropping allow you to successfully harvest yeast from high gravity (1.075+) batches?

learningmore · February 6, 2012, 11:59pm

Top Cropping is a lot more effort and gives you much less yeast, thus you will need to build it up. Use Mrmalty.com’s yeast viability calculator to tell you how much you need

When you top crop, you are getting very healthy yeast that are working. I used some top-cropped yeast from my friend and it was very active. When you get yeast from the trub left over you are including the dead (and dormat) yeast cells and will not be able to distinguish what is the healthiest.

Good luck`

shadetree · February 7, 2012, 1:02am

This is contrary to my experience with top-cropping - I get pure yeast, and lots of it, with little effort. Choosing a top-croppable yeast and fermenting in buckets are key.

learningmore · February 7, 2012, 6:46am

are you scooping the krausen?

When I and my friend did (ryan6458) we ended up with lots of krauen foam that eventually became a very small amount of yeast).

You must have very dense Krausen. (that is what the German woman said to me…)

roddy · February 7, 2012, 12:29pm

[quote=“learningmore”]are you scooping the krausen?

When I and my friend did (ryan6458) we ended up with lots of krauen foam that eventually became a very small amount of yeast).

You must have very dense Krausen. (that is what the German woman said to me…)[/quote]

I have never top cropped. I am just trying to gather some info. I have always read that top cropping gives you the healthiest yeast. But if multiple starters are needed to build it up, i’m not sure its worth the time.

shadetree · February 7, 2012, 12:58pm

[quote=“learningmore”]are you scooping the krausen?[/quote]A top-cropping yeast forms thick krausen that you scrape off the top and it’s kind of yogurty (3787 is a good example). It works best if you don’t take it when it first forms, but wait until the wort is about 2/3 done and the krausen is starting to fall and compact.

hopshead · February 12, 2012, 5:51pm

I have been top cropping yeast for almost two years. You will get plenty of yeast if harvesting from a top cropping yeast. White labs cal ale wlp001 is a very good top cropper. I usually place a scale under the collection vessel (flask for me) and I collect a consistent weight of top cropped yeast (about 100grams) at 48 hours after pitching. I don’t need starters either, but I prefer to make a pint of starter wort about 24 hours ahead of brew day to get the yeast awake if the top cropped yeast has been stored over two weeks.

My two cents on top cropped yeast: although not scientifically proven, I think top cropped yeast if collected within 48 hours of pitching is less susceptible to the affects of high alcohol beers, simply because there isn’t the high alcohol produced at 48 hours after pitch. Yeast collected post fermentation would have ill effects of high alcohol beers.

Also, I like to have about a pint of boiled/cooled water to put in my flask of top cropped yeast for storage if I won’t be brewing immediately after collecting the top crop.