Dropping new wort onto yeast cake

[Belter]

There is a lot of conflicting info in brewing and over the years I've come to understand that some is outdated and some is perpetuated by information on the internet being repeated without being back up with experience. I for one have done this a number of times.

One of the things I've come to realise over time is that although there is a lot of talk about over pitching the general consensus in many other places is that you can never have too much yeast. And... "Making a starter is always a good idea". I've always had better results by pitching perhaps more than I should. So I've come to disbelieve just how much of a negative effect over pitching can have.

The next one I'd like to get to the bottom of is pitching straight onto yeast cake. A massive over pitch onto dead yeast and previous break matter. I hear on a lot of American websites that people are brewing small beers and using that cake to make a big beer with no talk of rinsing or anything.

The reason I ask is I have a (very pale) saison in the fermenter in which I direct pitched a mixed blend of two saison yeasts from the yeast bay. I'd like to expland on it by making a darker earthy peppery 8%er and am considering dumping it straight on top brewing the new and kegging the previous saison on the same day.

I understand that the blends won't be in the same proportion after this brew but the blend is of two yeasts from famous saison breweries so it shouldn't matter if I get more DuPont than [inset other famous saison brewery].

Secondly does anyone have a recipe similar to goose islands Pepe Nero? Seymour?

Your thoughts?

Please only answer if you have direct experience of this as I know this could again attract comments from people who have read stuff in the right/wrong places online/in old literature.

[h_doody]

Don't drop it straight onto the yeast cake.

If you want to use the yeast again just scoop it up into a jar and use it as you normally would.

Dropping straight onto it is a bit rubbish as your FV won't be sanitised and you may be dropping onto a lot of dead yeast cells.

[Belter]

Don't drop it straight onto the yeast cake.

If you want to use the yeast again just scoop it up into a jar and use it as you normally would.

Dropping straight onto it is a bit rubbish as your FV won't be sanitised and you may be dropping onto a lot of dead yeast cells.

Have you ever done what I'm suggesting though? I realise the accepted wisdom is a bad idea but I'm asking if anyone has any experience to back that up.

Sanitising isn't an issue. The previous brew would have been infected otherwise.

What benefit does putting it into a jar have? it still contains dead yeast cells. Are you suggesting I rinse?

[bigrichlock]

I have dropped a barley wine on to a pale ale yeast cake and there were no noticeable off flavors and i dont believe the beer suffered any detrimental effects.

If anything the yeast is in top condition and ready for action, lag time is minimal, and yes you will be over pitching and this will just result in a cleaner final beer (to a point) but the benefits of using health yeast will out way any other issues

Things to think about tho are:

- rack the first beer off the yeast cake asap, as soon and the yeast has dropped i.e 7 days, longer the first beer is on the yeast cake the lower the viability
- trub, if using a plate chiller then you will end up with a fair bit in the fermenter
- sanitation is even more important
- it is important the yeast cake is broken up and the yeast is back in suspension - give it a good swirl before racking on to it or just poor into next fermenter
- if poring into next fermenter (as above) you don't have to add it all

Yes there are better was to do it than just racking on to the yeast cake but it is a well proven method, and works well.

Cheers

Rich

[Fil]

Im happy to reuse the sediment in the fv for a 2nd or 3rd fermentation with somethings, i have one on the go now. but not my beer. imho its about the degree of risk, with my beer which involves expensive ingredients and significant time, not just emptying packs and adding water, i dont want to take any extra risk..

I dont know what the numbers are but when simply reusing the sediment in a FV the probability of something unwanted getting established has got to increase. but the way probability works no matter what the odds some sod is gonna lay right at the end of the bell curve and get no probs after x00 resues, thing is you can guarantee he/her is a big internet mouth spouting the benefits.. and chances are if you follow suit you could just end up at the other end of the curve and come undone on your 1st attempt.

if its a quick kit brew go for it, your saving a significant amount of time compared to the 10-20 mins it takes to dilute the kit contents in water, tho if its an Ag brew you probably spent time deciding on and sourcing the best ingredients for and spend a day brewing, the 1/2 hour or so to clean and sterilise the fv and the time it takes to rinse the yeast, isnt that significant and its something to do during the boil

I now need to go n look up what the dangers of overpitching are! Know ive read it, just cant recall

[bigrichlock]

dangers issues associated with over pitching

- Overly rapid fermentation
- Very high pitching rates result in low yeast growth levels due to a lack of available nutrients - not enough nutrients to go around the large number of yeast cells
- Loss of wort sugars due to biomass formation
- Extreme over pitching can result in the yeast becoming stress by lack of nutrients and increased ester formation
- If cropping for further fermentations the quality of yeast may be low due to relatively high proportion of yeast cells being derived from original pitch
(above from Brewing Yeast and Fermentation by Boulton and Quain)

- Over multiple generations the yeast may not floculate as well (yeast health issue)
- Again over multiple generations attenuation may decrease (yeast health issue)

All the above problems are exacerbated over multiple generations and for a 2nd generation will most likely not cause an issue

From what I have seen most home brewers (including me) drastically over estimate the amount of yeast they pitch even when using starters. I would guess even with the best intentions Belter would have under pitched in the original fermentation there will be an over pitch in the 2nd batch, by how much? there is only one way to find out for sure, and that is to start counting yeast cells. However i doubt it will cause any real issue detectable.

The big issue here is sanitation, and risk of infection, the yeast you crop and pitch will have a bacterial count, but hopefully it will be very very very low, and the bacteria will be out competed by the yeast, just like most commercial breweries

The other real problem is for re-pitching yeast you really need to oxygenating the wort especially for high gravity beers but this is a different topic.

Rich

[Belter]

I only intend to do this once. I wouldn't do it again after that.

Has anyone found an oxygen setup for less than £60 yet? I'm close to pressing the button in the welduk disposable setup

[techtone]

I agree about conflicting information. All that matters is working out what works for YOU and not others. It can sometimes be a case of doing one part of the process one way influences what works in other parts of the process. So unless you follow someone else's compete procedure (including temperatures and equipment), then taking advise on one part can be irrelevant.

I have pitched onto the old yeast cake many times and never had a problem, although I usually choose to spilt into 2 and jar for future use. (I have kept jars in the fridge up to 6 months) Never personally had a problem. I haven't any experience going much over 6% though. I don't use a ferment fridge but I do try and brew when the termperatures are reasonably low for the yeast, so it doesn't get too active.

In terms of oxygen, I just use a large plastic spoon

[simmyb]

Here is what I would do. Not saying this is right or wrong but just what I would do.

I guess the main idea here is to get a good quantity of active yeast in the stronger brew. The day before or morning of your second brew, I would rack the first brew off the yeast leaving a litre of beer behind with the yeast. Swirl this up and pour into my 2 litre flask. Allow to settle for 10 -15 mins and pour into 2 large mayo jars which would leave about half a litre behind. I would guess this would leave most of the undesireables behind. Allow these jars to settle out with the lids slightly loose to allow for gas build up. Then, once you are ready to pitch your second batch you can add 1 or both of the jars. I would imagine 1 would be more than enough for a 7% brew without getting into ‘massive’ overpitch territory...

This way I can enure that the FV is spotless, the yeast has had a rudimentary ‘rinse’, the wort is fully aerated etc, but the gap between collecting and pitching is minimal ensuring a minmal lag time. If you only use one jar then you can rinse the second for short term storage for a future batch? My thoughts on pitching onto the yeast cake is that it’s just about saving a bit of time rather than making better beer...

Just my tuppence worth....

[PhilB]

Hi Belter

One of the things I never see (or hardly ever ) in the various threads on this topic around the various forums, is the temperature problem of dropping new wort onto a previous yeast cake ... I tend to crash chill my beers in the FV a day or two before I rack them for packaging nowadays and so, depending on how quick I can get my next wort ready after that, the yeast in the cake is likely to be somewhere between 5C and ambient ... if I were to be mixing a kit brew I would add boiling (or very hot) water into the FV first and add the kit malt extract and stuff into that water, to get it to dissolve, before topping up with cold water to adjust to pitching temp; and if I've been doing hop boils and/or hop teas then it can take a while to get down to a reasonable pitching temp. To do all of that I'd need to mix the kit up in a separate, sterilised FV, otherwise I'd cook the yeast in that cake, so where's the saving? ... an extract brew would be similar and when I do an AG brew and use my worth chiller, I usually chill down to low 30sC and then drop into the FV (from a height to aerate) which gets it down to mid 20sC, so whilst I may not actually cook the yeast in a cake if I were to drop that wort onto it, there's still likely to be a 10-20C temp difference between the wort and the yeast and so I'd be risking giving it some "thermal shock" ... so I'm probably always looking at dropping the wort into a separate, sterilised FV, then adjusting the temp of either the wort and/or the yeast cake, maybe adding wort in small amounts to adjust the temp of the yeast in steps ... so I'm really unsure how I'd actually benefit from the savings

If you want to use the yeast again just scoop it up into a jar and use it as you normally would.

What benefit does putting it into a jar have? it still contains dead yeast cells. Are you suggesting I rinse?

... it's the fact that I'd be cleaning and sterilising another container anyway that would encourage me to take h_doody's approach, personally. And with a small amount of yeast slurry I can adjust its temperature a little easier. I wouldn't rinse, but (I believe) skimming slurry from the top of the cake gets you proportionally fewer dead yeast cells and less of the rubbish, and if you use the "Repitching Yeast Slurry" option on the MrMalty yeast calc it'll give you the amount you need to pitch ... and you'll see that that's around 5-10% of the whole cake, so you'll be pitching around a 20th of the dead cells and rubbish into your next brew that you would have done had you dropped it onto the entire cake. Of course, you are the head-brewer

Cheers, PhilB

[Horatio]

I have done this many times without any noticeable difference in the final beer. I rack from fermenter to conditioning tank, leaving the yeast cake in the FV. I then run my cooled wort from the boiler straight onto the yeast cake. Beers made this way taste just like the same beer made with a fresh pitch of yeast. I have done this with beers that have been sold in the same outlet and nobody has detected any differences; because there are none. I don't do this as a matter of course just very occasionally when needs dictate.

I now fully expect to be shot down in flames by the better informed!

[HotHead]

I did this once when I'd accidentally killed the yeast that I was going to use. It may not be ideal, but in a pinch it works.

[rocket ronnie]

I have done this many times without any noticeable difference in the final beer. I rack from fermenter to conditioning tank, leaving the yeast cake in the FV. I then run my cooled wort from the boiler straight onto the yeast cake. Beers made this way taste just like the same beer made with a fresh pitch of yeast. I have done this with beers that have been sold in the same outlet and nobody has detected any differences; because there are none. I don't do this as a matter of course just very occasionally when needs dictate.

I now fully expect to be shot down in flames by the better informed!

The last three brews I have done this. I made a bitter 3.7% and used a packet of wilkos gervin yeast. When I racked off after the brew I scooped the yeast out and after putting in a porter brew 4.7% into the F/V I placed all the original yeast cake into it. It brewed OK.
Then last week I made up a dark Sarah Hughes Dark Ruby 5.7% using the yeast cake the same way. I admit I do not throw it onto the yeast cake but scoop it all out into a bucket and place it onto the brew at the start. I usually do this for four brews and found no differences. I stop after four brews as the yeast cake gets enormous. I buy another packet of yeast then to do four more brews, saves money. I only use these packet yeasts and have never used cultures etc.