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General Category => Yeast and Fermentation => Topic started by: phillamb168 on September 16, 2011, 10:49:59 AM

Title: Question on racking technique
Post by: phillamb168 on September 16, 2011, 10:49:59 AM
Say I have a beer I've had fermenting in a 150 L bucket, 38 L of wort, I pitched the yeast a day ago. Now say I take a fresh batch of just-cooled wort, and pitch it on top, bringing the amount in the bucket up to 76 L. Now say in two more days, I put another fresh batch of just-cooled wort into the same container. All three worts are the same style. Is the finished beer going to be much different from what I'd get if I had put each one into its own bucket? The end goal here is to allow me to "brew" 150L batches while putting off until later the purchase of expensive large capacity kettles.
Title: Re: Question on racking technique
Post by: jeffy on September 16, 2011, 10:58:17 AM
They do this all the time at small breweries and brewpubs when they have fermenters that are bigger than the brew kettle.  My local brew pub just installed two 40 bbl tanks, but they only have a 10 bbl brew house.  That means 4 back to back brewing sessions to fill each one.
Title: Re: Question on racking technique
Post by: hopfenundmalz on September 16, 2011, 12:16:31 PM
To add to Jeff's comments, Sierra Nevada has a 200 barrel brewhouse that fills 800 barrrel tanks.  Bells has a 50 barrel brewhouse (soon to up that to 200) that fills 400 barrel tanks.  They can do a couple of batches per shift in a production brewery.

I think your beer will turn out fine if you can crank out the total over 3 days.
Title: Re: Question on racking technique
Post by: Jimmy K on September 16, 2011, 01:05:38 PM
Dogfish has a 100 barrel brew house and some 600 barrel fermenters. The only difference is that the brew multiple batches per shift, 3 shifts a day to fill them. I don't know of they inoculate right away or wait until the last batch is complete.
Title: Re: Question on racking technique
Post by: phillamb168 on September 16, 2011, 01:06:51 PM
What if I were to rack wort over beer that had basically finished fermenting? Or would the yeast not be interested?
Title: Re: Question on racking technique
Post by: seajellie on September 16, 2011, 01:49:55 PM
I've had mixed results with that, the few times I tried it. The higher alcohol beers turned out rather funky... drinkable, but not as good as they could've been. Visually, it was obvious that the fermentation was not as healthy as the original fermentation. I presume the alcohol got in the way of love.

When I tried it with a lower alcohol brew and there was less "lag" time after the first fermentation finished the results were better. I think there's probably a line in there somewhere that's best not to cross...  but interested in what others have experienced.
Title: Re: Question on racking technique
Post by: tschmidlin on September 16, 2011, 05:29:52 PM
Like people mentioned, a lot of breweries do this, but their timeline is generally much shorter than what you are proposing.  I think if you can get 3 batches done in 2 days it will be totally fine, but I wouldn't wait a couple of days in between.
Title: Re: Question on racking technique
Post by: euge on September 16, 2011, 06:35:01 PM
What if I were to rack wort over beer that had basically finished fermenting? Or would the yeast not be interested?

It would ferment but you're better off adding while the yeast are actively fermenting. Full krausen would be optimal IMO.
Title: Re: Question on racking technique
Post by: glastctbrew on September 16, 2011, 06:53:09 PM
Phil,

Check out this thread  from probrewer.com  http://www.probrewer.com/vbulletin/showthread.php?t=21618    Granted the volumes are larger but it is about blending multiple batches in a single fermenter and it should still give you some process ideas.  

Title: Re: Question on racking technique
Post by: Jimmy K on September 16, 2011, 07:34:55 PM
What if I were to rack wort over beer that had basically finished fermenting? Or would the yeast not be interested?

I'd make all wort additions before or at peak krausen. Adding new sugars to yeast that are going dormant is just asking for off flavors.
Title: Re: Question on racking technique
Post by: Thirsty_Monk on September 18, 2011, 09:06:00 PM
Like people mentioned, a lot of breweries do this, but their timeline is generally much shorter than what you are proposing.  I think if you can get 3 batches done in 2 days it will be totally fine, but I wouldn't wait a couple of days in between.
I agree.
You can do multiple batches but you should do them within the two days.
One thing I like to point out is then you pitch yeast after the first batch you have to match your racking wort temp to your fermenter temp. Sound simple enough but it is something to consider.
When I brew double batch I brew both batches in one day.
Then I cool the 10 BBL over night to pitchable temp (50F) and I pitch next day.
Title: Re: Question on racking technique
Post by: tubercle on September 18, 2011, 11:21:49 PM
What if I were to rack wort over beer that had basically finished fermenting? Or would the yeast not be interested?

I'd make all wort additions before or at peak krausen. Adding new sugars to yeast that are going dormant is just asking for off flavors.

What specific off flavors would be involved?
 Adding new sugar over a period of a week or so is common in raising the alcohol content of wine without any effect.

Just asking....
Title: Re: Question on racking technique
Post by: bluesman on September 19, 2011, 01:24:58 AM
You could add fresh wort at any time, but ideally adding the wort when the yeast are most active would make it easier for the yeast to ferment the additional wort, as they are more energized and would not have to exert as much energy, therefore making it easier and less stressful for them to ferment the fresh wort. All in an effort to make better beer.
Title: Re: Question on racking technique
Post by: phillamb168 on September 19, 2011, 11:54:47 AM
Thanks for the great info everybody. I think I'm going to give this a shot with my next pils.
Title: Re: Question on racking technique
Post by: Jimmy K on September 19, 2011, 12:38:36 PM
What specific off flavors would be involved?
 Adding new sugar over a period of a week or so is common in raising the alcohol content of wine without any effect.


Never tried it, so I can't really say. Maybe I'm just guessing, but brewing yeast management is all about creating happy yeast. I know when yeast start running out of sugars to eat, they enter a dormancy phase where they build glycogen reserves in their cells. The glycogen reserves are used to stay alive without food and for the first few hours after receiving new food (wort). But if they get new wort partway into the dormancy phase, they are basically not ready to become active again.

Brewers worry about yeast health and pitching rates far more than winemakers and I'm not sure why that is. Also, there may be a difference between adding small amounts of sugar repeatedly over a week - which would keep a low activity level active - and adding a new batch of wort - which would add a lot of sugar and push the yeast back into a higher activity level.
Title: Re: Question on racking technique
Post by: tschmidlin on September 19, 2011, 11:59:57 PM
What if I were to rack wort over beer that had basically finished fermenting? Or would the yeast not be interested?

I'd make all wort additions before or at peak krausen. Adding new sugars to yeast that are going dormant is just asking for off flavors.

What specific off flavors would be involved?
 Adding new sugar over a period of a week or so is common in raising the alcohol content of wine without any effect.

Just asking....

I would recommend adding any sugars to the wort either before or after fermentation, but not during.  The main reason is that the first thing the yeast will ferment is the simple sugars (glucose and fructose), then it will switch to more complex sugars (maltose, maltotriose, etc).  The presence of glucose inhibits the fermentation of the more complex sugars.  If you add additional glucose while it is fermenting maltose, the cells will stop fermenting maltose and switch to glucose.  Wen the glucose level drops again, they will switch back to fermenting maltose.  This may have an affect on the overall fermentation performance, and might not give repeatable results.

Adding sugar at the end though, seems fine to me.  I do it when I (rarely) add fruit to beers, the yeast don't seem to mind.  I don't have a lot of experience with it though.
Title: Re: Question on racking technique
Post by: bluesman on September 20, 2011, 12:27:59 AM
It also depends on what you are trying to achieve. If you want to dry the beer out somewhat, then adding some simple sugar during high krausen will help do that. I agree with Tom in the order with which the yeast will ferment sugar and I also think the yeast prefer to keep things going as opposed to stopping and starting again (not that they won't). It involves more energy for them and ultimately can affect the flavor profile of the final beer.

More often than not, I prefer to let the yeast do their job in one shot. In Phil's case he may opt to keep feeding the yeast continuosly, allowing the yeast to consume all of the simple sugars first and letting them finish by consuming some of the maltose and maltotriose. As long as they are healthy to begin with, and have enough oxygen to sustain the level of active fermentation required to finish, they will consume most if not all of the sugar available. Temperature and yeast strain should also be considered.
Title: Re: Question on racking technique
Post by: phillamb168 on September 21, 2011, 08:59:13 AM
It also depends on what you are trying to achieve. If you want to dry the beer out somewhat, then adding some simple sugar during high krausen will help do that. I agree with Tom in the order with which the yeast will ferment sugar and I also think the yeast prefer to keep things going as opposed to stopping and starting again (not that they won't). It involves more energy for them and ultimately can affect the flavor profile of the final beer.

More often than not, I prefer to let the yeast do their job in one shot. In Phil's case he may opt to keep feeding the yeast continuosly, allowing the yeast to consume all of the simple sugars first and letting them finish by consuming some of the maltose and maltotriose. As long as they are healthy to begin with, and have enough oxygen to sustain the level of active fermentation required to finish, they will consume most if not all of the sugar available. Temperature and yeast strain should also be considered.

What I don't want to do, though, is go down the road to continuous fermentation in the sense that a lot of the breweries in the 70s tried. I'm concerned about diacetyl with this technique, so what's the difference between continuous fermentation and for example stepping up a yeast culture? Or should I just RDWHAHB as far as this is concerned?