Pitching on Roselare yeast cake

Hello all. First time posting.

We are about to bottle a Flanders Red and plan on brewing a Tart of Darkness clone right after. Since we will have a nice yeast cake sitting there, I wondered if we could just pitch right on top of it. I've researched a little and saw that next generation Roselare will be more sour and complex (which I like).

Any reason we shouldn't do this? Should we pitch a fresh Roselare pack with it just to be safe? Or add US05 to be safe as well?

Thanks!

While it certainly will ferment the beer, the cultures will not be in the same ratios as before, and the ratios you now have will depend on the fermentation conditions of the previous batch, and how long it was sitting. Your results may vary.

Personally, due to the time investment in a sour, Id pitch a fresh culture. Others with more sour experience should speak up.

Welcome!

First gen Roselare tends to produce a subdued sour character. Many people have experienced increased sourness with second and third generations, and a subsequent fall off if used after that.

I made a Flanders in 2013 that was mildly sour. I racked a Kolsch I got from a Monster Brew on top of the yeast cake early last year, and kegged recently. The result is a much more sour beer that I really enjoy. I pitched a mason jar's worth of bugs into a Flanders Brown, and will be doing so with another Flanders Red this Saturday (along with the Melange Blend from The Yeast Bay).

It doesn't hurt to save some of the cake and experiment. Good luck.

misled_drummer said:

Welcome!

First gen Roselare tends to produce a subdued sour character. Many people have experienced increased sourness with second and third generations, and a subsequent fall off if used after that.

I made a Flanders in 2013 that was mildly sour. I racked a Kolsch I got from a Monster Brew on top of the yeast cake early last year, and kegged recently. The result is a much more sour beer that I really enjoy. I pitched a mason jar's worth of bugs into a Flanders Brown, and will be doing so with another Flanders Red this Saturday (along with the Melange Blend from The Yeast Bay).

It doesn't hurt to save some of the cake and experiment. Good luck.

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Thanks, Misled!

Do you recommend supplementing the existing cake with US05 or adding fresh Roeselare? Girafe's comments are ones I've seen before. Concern over the ratios. But I think the benefit of using second generation (and more sour) roeselare may outweigh it. Which is why I'm asking.

I plan on doing exactly that and then blending the first batch and second batch 50/50. Got my first batch started last weekend. I plan on waiting 3 months before racking it to a secondary and then adding fresh wort on the cake.

MFerBrew said:

Thanks, Misled!

Do you recommend supplementing the existing cake with US05 or adding fresh Roeselare? Girafe's comments are ones I've seen before. Concern over the ratios. But I think the benefit of using second generation (and more sour) roeselare may outweigh it. Which is why I'm asking.

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I think adding some US05 or other neutral yeast is a good idea as you will ensure that the beer gets a proper primary fermentation. I recommend pitching the neutral yeast and your bugs at the same time.

In a Q&A on Brew Strong about sours, A JZ highly recommended making a starter for Roselare, even though it is likely the ratios would change.

The Yeast Bay also recommends the following in making such a starter:

"Due to significant variation in growth rates and conditions among Saccharomyces, Brettanomyces, Lactobacillus and Pediococcus, starter cultures for complex blends containing multiple types of organisms may alter the proportions. An important aspect of making a starter culture for these blends is to ensure the temperature is not too hot, which will greatly increase the metabolic activity of the lactic acid bacteria. If the pH drops significantly due to acid production, this may inhibit yeast growth and drastically change the balance of the culture. A semi-aerobic starter made at a temperature of ~66 -68 ºF for ~24-36 hours will be sufficient to bump up the cell count while keeping the lactic acid bacteria population under control."

Something else I suggest is that if you plan on harvesting yeast from sour batches, you do so before adding fruits or other additives.

I left my sours in primary for the entire time, added fruit, and then kegged due to the limited number of fermentation vessels I have. Washing the fruited beer was a pain in the butt and significantly reduced the amount of yeast I was able to harvest.

On a related note...

If I have something going on Roselare (and several bottle dregs) that's ~9 months into aging and want to inoculate a new batch would I be better off doing so by racking the current beer to a new vessel and the new beer onto the cake.... or just dumping some of the first beer into the wort of the 2nd? How much of batch 1 would I want to add to batch 2 if I go that route?

ruger988 said:

On a related note...

If I have something going on Roselare (and several bottle dregs) that's ~9 months into aging and want to inoculate a new batch would I be better off doing so by racking the current beer to a new vessel and the new beer onto the cake.... or just dumping some of the first beer into the wort of the 2nd? How much of batch 1 would I want to add to batch 2 if I go that route?

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Considering these beers are meant for long term aging and the high likelihood of dead yeast cells in the trub, I would suggest the following:

1. Rack old beer into new vessel leaving behind yeast cake
2. Wash the yeast cake via methods outlined in this forum
3. Pitch washed yeast, maybe two mason jars worth, into new beer. If storing, you will have to make a starter whenever you're ready to use the culture.

This method will provide you with the "cleanest" yeast possible. However, many sources say that autolysis is not an issue in sour beers with Brett as the Brett will eat the dead cells.

Another benefit is that you will have a few jars of your own house bugs to use in future batches, whereas merely dumping on top of the yeast cake prevents you from doing this.

I've used both methods, but have only tasted the results of pitching on top of the yeast cake without washing. As mentioned above, I got a much sourer beer without any off flavors.

So I can't tell you how it will turn out, but I did exactly what you are talking about. Brewed a Flanders red. Barrel aged it for a year and then threw some slurry into a Tart of Darkness clone. I figure it will be what it will be.

Won't know for another 8 months what it will taste like

I consider the first batch on fresh Roeselare to be a sacrificial batch. It is generally bland and barely sour if at all. Definitely put another beer on the cake and let it ride for a year. Throw some bottle dregs in from commercial sours if possible and it will be a more interesting beer. Split the cake and do a couple of batches. You can never have too big a sour pipeline.

MFerBrew said:

Thanks, Misled!

Do you recommend supplementing the existing cake with US05 or adding fresh Roeselare? Girafe's comments are ones I've seen before. Concern over the ratios. But I think the benefit of using second generation (and more sour) roeselare may outweigh it. Which is why I'm asking.

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Another method would be to pitch the USo5, let it ferment until the yeast drops out, (two weeks?) then transfer to carboy with rosalare yeast cake.

Pitch straight onto the cake. You will probably need fresh sacc, but wait 3 to 4 days to do so. Let the bugs get to wotk before any alcohol is produced. S-05 may not be the best yeast since it is a clean yeast.

I would rack as the sacc slows down to get it off the really old trub, but still carry over a lot of sacc yeast.

Why wouldn't you want a clean yeast?

Brett feeds on dead yeast and will convert esters to delicious fruity and funky compounds. Most of us want to encourage those things so using an under pitched Belgian yeast and leaving the beer on the cake is standard practice.

Interesting. Which yeast would you recommend? There are so many belgian strains. Remember, this will be for a Tart of Darkness clone which is a unique style.

MFerBrew said:

Interesting. Which yeast would you recommend? There are so many belgian strains. Remember, this will be for a Tart of Darkness clone which is a unique style.

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I've used White Labs' Abbey or Trappist strain for a few of my sours that I wanted some Belgian character, such as my RR Consecration clones.

I've brewed Tart of Darkness and you want a neutral yeast such as Cal Ale or S05.