Re-fermentation and Yeast count

[pcampo]

I brewed a Belgian Dark strong, and plan on re-fermenting in the bottling and conditioning.

From reading "Brew like a monk", Many of the Belgian breweries use any where from 1-2 million cells per milliliter for bottle conditioning.

Using "Brew like a monks" recommendations for the cell count, and considering that I have 5 gallons which is about 18,900 ml, that puts me at anywhere from 19 billion cells to 40 billion cells total to pitch.

Here is my question/problem: A dry yeast packet (which is what im going to use) has about 230 billion cells. MY LHBS and people on this site, recommend just using a whole packet, but that is WAY over the amount that "BLM" recommends. And also considering that the Belgian breweries now centrifuge there old yeast out before bottling, that means they have less of the old yeast in solution then I do.

With 230 billion cells and old but active yeast still in solution how does this not call for a bottle bomb, given that Belgians use about 80-90% less yeast than a dry yeast packet, and they have a "cleaner" solution than I do, and their beers are very effervescent?

 

[insanim8er]

huh? You're counting yeast for bottling? This post is very confusing... It sounds like you're way over thinking this.

If you're talking about bottle conditioning, why are you so worried about your yeast count? The yeast in suspension will handle the carbonation.

Or am I totally off on what you're trying to get at?

 

[m1batt1]

I'm kind of confused by your post as well. However I will touch on one point. Assuming you let fermentation finish and didn't severely underpitch in the place having a high cell count for your yeast will not cause bottle bombs. Over carbonation/bottle bombs only happen if you didn't let initial fermentation finish, you added too much priming sugar, infection, or a combination of those.

 

[pcampo]

Sorry guys, Yeah this sounds confusing. Let me re-explain

Traditional Belgians beers, are "re-fermented" in the bottle. Meaning, that after fermentation is done, and its time to bottle, they re-pitch some new fresh yeast. Some claim, this type of bottle conditioning adds to the complexity of these Belgian beers. Also, with a high gravity beer, its only a gamble if you hope to see high carbonation volumes (3.5-5 volumes CO2) using only the old yeast in suspension.

I want to mimic some of these techniques. So I want to use the same amount of yeast that the Belgians use.

 

[pcampo]

What I am asking, or the problem I am introducing, is that if I were to go by what the book "Brew like a monk" suggests, then that means I would only use a tiny bit from a dry yeast packet, about 2 grams to be exact. While the contradiction is that some people recommend using a WHOLE packet (11.5 grams) to re-ferment.

I don't know which to use, 2 grams, or the whole packet?

Are my calculations wrong perhaps?

 

[stpug]

If I recall correctly a hazy beer contains 1 to 2 million cells per milliliter so unless you're going to centrifuge yourself then I wouldn't worry about repitching any yeast at bottling time unless you want to bottle with a different strain

 

[pcampo]

Thanks for the input stpug.

I think I am still going to re-pitch some yeast for two reasons: from what I read, the idea behind it is that with a high gravity beer, the yeast are too tired and over worked to produce a carbonation as high as a Belgian. Maybe this theory is true, maybe not, however if I am trying to replicate something like a Rochefort 10, and if re-fermentation is crucial to obtaining some of those characteristics, then I have to make sure im getting the right amounts in at bottling time.

Maybe its all a myth, I don't know. But only way to know is to try.

But I think I will just use half a packet and see what happens.

 

[insanim8er]

Ya I think you're over thinking it a bit... I looked it up since I never read the book.

Denny Con posted:


According to "Brew Like A Monk" by Stan Heironymous, Belgian brewers rarely (but not never) use more than a single yeast strain. He says that they have so much of the primary yeast around that it doesn't make sense to go out of their way to use another. – Denny Conn♦ Dec 11 '10 at 3:32 (http://homebrew.stackexchange.com/questions/2899/triple-fermented-but-why)

Other stuff I read is they may use a second strain to impart some other flavor profile (like you said, adding complexity) or to dry the beer out even more than what the original yeast strain can. They also bump up the heat to help dry it out... That's what I do with my Saison

If you're worried about over pitching, do a pinch of yeast... I really don't think it would impart such a dramatic profile difference by simply bottle conditioning/carbing the beer considering its such a small amount of sugar. I read a little that talked about actually adding more sugar to do a second fermentation... then bottle conditioning is the "third" fermentation.

I don't understand the reason for different yeast for bottle conditioning since a lot of home brewers bottle carb their beers (big beers too) with the residual yeast.... But for some really big beers some will use champagne yeast... So who knows maybe there is merit in it. Good luck.

 

[pcampo]

Thanks for the input insamin8er.

Its true that our abbey friends, rarely use a second strain. However, it is certainly true that they use fresh yeast (top cropped) at bottling time. I am not really talking about developing another yeast flavor profile. There is something about the fresh yeast, and bottle conditioning time that adds depth to the flavor (so I have read). Also, I would imagine it would be hard to obtain high volumes of CO2 only using the residual yeast.

 

[kshathra]

pcampo: You and I are going through something very similar right now. I also just read BLAM and have just brewed a Belgian dark strong ale using the Rochefort yeast but with my own recipe. Mine's not a clone recipe by any means. I'm more sort of messing around with different concepts and trying to find recipes that are very good but don't conform to style. This one, for instance, uses some roasted grains for an off-style coffee back note, and has some flaked barley and oats to make the mouth feel rich and silky. Also no sugar because I forgot to pick it up at the LHBS and didn't realize until the end of the boil. Tasty so far but I won't know for sure until around Halloween.

With regards to your original question, I don't think moderately overpitching yeast at time of bottling will do much to negatively impact your beer. I think the big result would be slightly more sediment but probably not a measurable amount. I think the bulk of the effect will be dictated by whether you have some minimum number of cells to eat the sugar present, and how much sugar you have present to be eaten by said cells. If you pitch 1 or 10 mil/mL but use the same amount of sugar in both cases, your results should be the basically the same I think as long as 1 mil/mL is enough to actually ferment out the sugar you added. If I were you, I would probably pitch the 2g or whatever you calculated to be the monks' pitching rate and not worry too much about all the cells still present in the beer. They will be tired and partially out of commission due to the high gravity ferment, and even if a lot are viable it shouldn't damage your end result.

As a side note, I'm really thinking about brewing another beer, probably an IPA since I haven't made one in a while, but doing the Orval-style natural carbonation using Brett. Reading that book was a terrible idea. Now I can't possibly brew enough to satisfy my desire to replicate the techniques they talk about in that book!

 

[peterj]

The amount of yeast you add will not affect the level of carbonation in the beer. The only thing that affects that is the amount of sugar you add at bottling. So adding the whole pack of yeast will only result in more yeast sediment in the bottle. The yeast have a set amount of sugar that they can turn into CO2 and they will eat it all, and the CO2 will be limited by the amount of sugar added. As long as there is enough yeast (which there usually is) and you add the correct amount of priming sugar, your carbonation will be right.

Any homebrew that is bottled goes through a "re-fermentation" in the bottle. That's how we all create carbonation. And almost all of the time it's not necessary to pitch fresh yeast at bottling. There's usually plenty of yeast left to eat through the added sugar. Even in a high gravity/high alcohol beer it's not really necessary to add more yeast. It may take a bit longer for the yeast to work through the sugar, but it shouldn't take too long. Yeast are a lot hardier than your giving them credit for. Maybe if you have bulk aged the beer for 6+ months and/or lagered it for months and most of the yeast has dropped out, then you should worry about pitching more yeast at bottling.

Also, you're not really going to get any flavor characteristics from the yeast fermenting the priming sugar (especially if it's the same strain). It's just not enough food for them to create any noticeable flavors. If you bottle with something like Brettanomyces then you will definitely get flavor from that breaking down all the unfermentable sugars and esters in the bottle over time. But I don't think that's what you're talking about.

Hope this helps!

 

[kshathra]

Uh, just noticed I wrote moderate over pitching "will" do something. Should have read "will not".

 

[pcampo]

Thanks for the input!

 

[pcampo]

Reading that book was a terrible idea. Now I can't possibly brew enough to satisfy my desire to replicate the techniques they talk about in that book!

I know exactly what you mean.