[phillamb168]

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.

[jeffy]

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.

[hopfenundmalz]

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.

[Jimmy K]

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.

[phillamb168]

What if I were to rack wort over beer that had basically finished fermenting? Or would the yeast not be interested?

[seajellie]

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.

[tschmidlin]

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.

[euge]

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.

[glastctbrew]

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.  

[Jimmy K]

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.

[Thirsty_Monk]

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.

[tubercle]

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....

[bluesman]

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.

[phillamb168]

Thanks for the great info everybody. I think I'm going to give this a shot with my next pils.

[Jimmy K]

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.