Top cropping reference log

[greenxpaddy]

Scooping yeast from the top of an active fermentation produces the cleanest yeast for a future brew and enables the brewer to get on with another batch before waiting for the current batch to ferment out and settle. It is possible to tip 1/5th of the current fermentation into a new batch of the same size as the first batch at high kreusen (around 48hrs point) but this will mix the gyle and is best left for a rebrew of the same exact beer.

Top cropping however with different yeasts, even top fermenting ale yeasts, seems a little hit or miss. If you are relying on top cropping for your next brew and it doesn't go your way it is quite annoying and mucks up your schedule. Rather than leave this all to chance I thought it would be a good idea to have a brewers log of top cropping attempts for reference. The key information I think would be appropriate is

Yeast Strain
Fermentation Temperature
Total batch size
Total thick yeast recovered, once refrigerated and settled (if need be)

By taking the last two bits of info it can be assessed what % of the total yeast present is available for top cropping and will give a good indication of the top crop-ability for those conditions. Clearly not all of the available top yeast is going to be recovered if you get sufficient, but within the brewers notes you could add how much more you estimate you could have recovered if you had wished

I would suggest so that the log is easy to scan the additional notes should be best left to a minimum.

Lastly, total yeast available is presumed to be 5 times that of the total pitch, which is presumed to be the recommended Mr Malty pitch for the batch.

Hope that all makes sense, and I hope others will see the benefit of the log.

[greenxpaddy]

Wy1028 London Ale (WLP013)
17C rising to 18C
150L
100ml yeast recovered (~5%)

Poor top crop, yeast only created a light foam kreusen

[greenxpaddy]

Wy1028 London Ale (WLP 013)
21.5C flat
165L
100ml yeast recovered (~5%)

Very active fermentation and kreusen, but to summarise this is not a good top cropper.

[greenxpaddy]

Wy1469 West Yorks ( No WLP equiv - supposedly Timothy Taylor)
20C flat
165L
400ml yeast recovered (20%) More available. Thick yeast started at 48 hrs.

Steady kreusen not needing too much head room, so far looks a very decent top cropper

[seymour]

greenxpaddy, I love, love, love this concept. Keep up the good work!

Bear in mind, though, that nearly all commercially available yeast as we know it has been conditioned for convenient usage on modern cylindro-conical fermentors. This means that even with strains which originated from fabled top-cropping breweries, many of their best top-cropping behavior patterns have been (temporarily, at least) bred out of them.

One of the most interesting things I learned from the Yeast book is that Chris White himself encouraged reusing a yeast selection at least 3 times because only then has it adapted enough to perform best on your particular setup! This, when he personally stands to benefit from people buying a new vial for each batch, what a guy! He went on to explain differences in performance from the same yeast when repitching cells cropped from the top at peak fermentation versus washed from the bottom after fermentation ends. So, what I'm saying is that your observed "top-croppability" could be greatly enhanced a few generations on, even for the exact same strains you've already tested.

[greenxpaddy]

Absolutely. By reusing top cropped yeast I will select top cropping characteristics but easier to start with a good top cropper in the first place.

Word of warning...go too far and you might end up with a temperamental yeast like Hopback yeast.

So I would suggest that after a couple of generations yeast should be collected two thirds from the top and third from the yeast cake at the bottom, which will also reduce trub too and mean less/no yeast washing is needed and getting to over-selection will take longer

[seymour]

True that, carry on

[monkeyboy]

WLP530 - Abbey Ale. True top-cropping monster. You'll have more yeast than you know what to do with.
Temp 20C rising to 26C (deliberately)
23L
amount: tons of the stuff. threw loads of it away. Sorry not to be precise.

[greenxpaddy]

You little Monkey. Without accuracy there is no science.

But we get the gist! It's a top cropper.

[WishboneBrewery]

Slightly off topic but the yeast at work goes like this:
Saltaire (Originally Thwaites yeast) pitch around 10KG into 20BBL @ 1040.
Its a Top Cropper.
We rouse via pump every 4 hours for 20mins.
We skim after reaching our Chill Gravity - 17c for about 24 hours.
We skim to keep upto 3 buckets of 10kg each, the latter buckets being more fluffy.
The yeast is kept in the fridge at around 4c until it is re-pitched (usually within 7 days), yeast is Acid Washed every 4th Pitch.
*Repeat*
For the most part Lower OG beers produce less yeast, we try not to keep too much yeast from darker beers as a precaution for not flavouring our lighter beers, if we don't rouse we get less yeast to crop.

[kane]

We rouse via pump every 4 hours for 20mins.

When you say via pump, is the yeast pumped from the bottom of the fermenter and then sprayed over the top of the fermenting wort? Like in the yorkshire square system?

Does this happen throughout the fermentation?

How does this correspond to not introducing oxygen in the finished beer? Is it due to the characteristics of the yeast, e.g. being able to clean up lots of oxygen before the beer becomes oxidised? Or can this be done with any yeast?

Sorry to interrupt the thread!

Cheers,
Kane

[WishboneBrewery]

Good questions I can't fully answer.
The fermenting wort is pumped from the bottom of the FV and back thru the yeast head, pretty close to the Yorkshire Square as you said.

[greenxpaddy]

What chemical do you acid wash with and how do you do 3 buckets worth, do you have a special vat with stirrer?

[WishboneBrewery]

We wash with Phosphoric Acid and we do it with a brewers paddle in the bucket + pH meter.

[greenxpaddy]

Sounds messy....Well I could certainly make amess doing that