Fermentation and double (triple?) batching

[Sir Brewsalot]

Some time in the next 6-12 months, I'm going to need to add some fermentation capacity. I've got a 10bbl brewhouse, and am looking at adding a 20bbl fermenter so that I can double-batch with back-to-back brews.

I've never heard of doing more than 2 before, but what's the limiting factor in the number of successive brews one could run into a single fermenter? In other words, if I went for a 30bbl fermenter, could I triple batch?

Thanks,
Scott

[tarmadilo]

I've double-batched two ways: two batches in the same day, and two batches in successive days. No problems. So, I guess you'd be okay to brew two batches on day one, and then a third batch on day two.

I'd think one limiting factor would be whether you could control the fermenter temps with just the first batch in there, but I reckon if you put, say, 65F degree wort in the fermenter, it shouldn't raise that much in three hours while you're brewing batch two...

Hmmm...

Cheers, Tim

[Sir Brewsalot]

Thanks for your response Tim. Sorry - I guess my original post wasn't very clear.

I've double batched on two consecutive days, but I have a temporary operational limitation that keeps me from doing two per day.

What I was getting at was this: What would be wrong with triple batching across three days into a single fermenter? Yeast behavior? Temperature control?

I figure putting in a 30bbl fermenter doesn't cost that much more than a 20bbl, so I may as well get more capacity if it will work.

Thanks,
Scott

[tarmadilo]

Well, that makes the question of how well you can control the temps with the fermenter one-third full a much more important one! I expect that if you can handle that one, three days worth of brewing wouldn't be a problem.

Anyone else?

Cheers, Tim

[jay]

I have worked at breweries that put up to 6 brews into a fermentor. The limit is based on the design of your brewery. I wouldn't add additional wort after 36 hrs.(absolute MAX). The other key is to only add air/oxygen durring the first brew. I have worked in both large and small breweries, the large breweries have complex systems for handling aeration and chilling. I suggest brewing two batches the first day and a third batch on the secound day. This type of schedule has worked for me in the past. Aeration durring the later brews can cause excessive foaming, loss of head retention, etc. Your yeast should be pitched durring the first brew and should be ample for the entire fermentor volume. Spreading the brews accross several days can cause many complex and difficult problems to arrise. I'm sure that some of the yeast suppliers will be able to better explain the mutation, and flavor profile changes that might be caused. In your case it is possible to save the business money, but additional effort is required on your part. Only you can make that choice, but multiple brews have worked well for me.
Graydon

[zbrew2k]

You can double batch over two days, although over three days is asking a bit too much.

Yeast growth can cause problems, mainly that you feed the fermentation again after lag phase and can lead to high peak cell counts. This can translate as higher process loss down the road.

Fermentations are vigorous! You will have to see what works with your yeast. I had a system with O2 aeration instead of air. We did double batches brewed over two days. Each brew was aerated through its cooling cycle. Process losses increased on these fermentors due to creating too much yeast. This was a problem. We ended up shutting off the O2 halfway through topping the second brew. Fermentation was still ok, no problems finishing, and process loss came down about 2-3%.

First brew, pitch normally, or slightly under. 24hrs later, top. Get a cell count before topping. Fermentation & cell count should be on its way. Top the fermentor slowly at first. You can knock CO2 out of the wort and cause excessive foaming and losses by hitting it with full flow. (Thats pretty exciting topping a 200bbl fermentor the second day at about 2 bbl/min with the second brew. We thought the fermentor might liftoff like a rocket! hahah)

Get a cell count on the freshly topped fermentor. Monitor your fermentation to see what kind of count you get at peak. Note differences in your normal fermentation cell count profile.

Now this kind of points to "why not top again on day 3?"

I seem to remember some research not recommending this, but can't point to it.

You would be feeding the fermentation at a suboptimal point for yeast growth. Remember the flavor of your beer comes from the proper amount of yeast growth. That is the main reason immobilized yeast columns for primary fermentation have never been popular or widely accepted. Yeast has to grow and multiply to give us the best flavors. Grow too much though and you throw away beer with the spent yeast.

Also, you know your yeast and process best, so you will have to modify this info for your conditions.

Good luck,
B

[gitchegumee]

I'm with Jay's opinion the whole way. I've added 48 hours later for slow starting lagers. I've asked Dr. Lewis about this at a conference, and he recommends NOT doubling (or tripling) up batches. I totally disagree and so do many, many other brewers. Made an interesting discussion when the crowd gave him advice to the contrary! I've also asked Wyeast about it and they told me that if I get what I want and watch my yeast count, then that is my best guide. It all depends on gravity, yeast strain, pitching rate, temperatures, etc. I'm at a plant in Mexico right now that has a 45 BBL brewlength into 180 BBL fermenters. This is a four vessel system, however and two days would be the maximum between start and finish. If you buy this fermenter new, specify the probe to be below the 1/2 or 1/3 mark. It's done all the time. If it's a used fermenter, add a thermowell. That's easy, too. To recap the other's points; pitch and aerate only the first day, discharge the crap from the cone on the second day, top up as normal. Makes the second day that much easier without dealing with yeast and aeration. Good luck, although I don't think you'll need it. This will be a piece of cake. Cheers!

[Sir Brewsalot]

It just occurred to me that if you had a real concern about how this might effect the yeast's behavior, you could always hold off pitching the yeast until day 2 of a 3 day "brew set". Though one could argue it's probably a far riskier proposition overall.

Great discussion everyone - keep 'em coming!
Scott

[gitchegumee]

It is my opinion that you should NEVER wait to pitch yeast. And I forgot to mention the added benefit of multiple batch fermentation of saving chemicals and time by cleaning two or three batches worth of fermenter at one time! Talk about an easy brew day!

[David Quinn]

I think very soon we will have the same problem. 10bbl brewhouse, but a 20-30 bbl need. Ive been thinking about a 20bbl tank to use for blending two 10bbl batches, not actually fermenting 20bbl in the same tank.....

[BigWilley]

What is your limiting factor on brewing twice a day? Maybe adding a whirlpool tank as a seperate vessel would solve your problem. The whirlpool vessel does not need to be jacketed etc. should be cheap compared to fermenters. i worked in a brewery that brewed 8 15 bbl batches into 120 bbbl tanks over 48 hrs (two shifts per day). The limiting factors are usually hot water and a Whirlpool vessel to hold a finished batch. A two brew day for bone individual would not be too long provided you had a vessel (whirlpool) to hold the first batch while you are lautering the second.

[tarmadilo]

Yeah, just getting a good, perhaps oversized, hot liquor tank can really shorten turnaround time between batches. At one micro where I worked, having a 1000-gallon dairy tank piped into the steam permitted brewing three batches a day, with initial mash-in at 6 am, and the last batch finishing up just at about 1 am. Of course we had three brewers working...

Cheers, Tim

[Faustino Silva]

Three brews in a day will work nicely, Six hours per brew makes for a long day. I run Oxigen on all the brews and pitch 1 1/2 yeast count. You should finish clean up within 18 hours. Where were you going to put all the beer, won't that overload your bright tanks.

Cheers
Faustino

[Trub-Man]

The key is to not add o2 after the aerobic phase for yeast metabolism, adding o2 into anaerobic phase will only be scrubbed out by the co2 and could possibly shorten your shelf life/oxidation. If you want to produce a stable product without high airs don’t add air after 24 hours for lagers (not sure for ales, higher temp so would assume shorter time), you can 'squeeze in' another brew before 36 hours with out air but be careful with attenuation, might want to over pitch to accommodate the last brew, grow the yeast to accommodate the last brew which would mean over oxygenating the first few brews. Pitching in at a colder temp will help slow down the 'lag/aerobic' phase which will give you some time to top up the fermentor. I believe you can pitch upto 32 hours MAX, if and if only your yeast is still in lag phase or close to it. That is to say it has only dropped 0.5 to 1.0 Plato in the last 24 hours anything lower in it is most likely in anaerobic phase and fully fermenting NO air!!!!

Disclaimer, I know what I am talking about, honestly. But am posting with a few drinks in my belly, so might not make sense. If you have any questions please feel free to PM me. Cheers, Happy Fermenting

[Faustino Silva]

Three brews one after the other, is just 18 hours. That should double your yeast count, I would suggest acid washing on a regular basis, to make your yeast counts more consistant. Oxigen will not be a problem in this time frame.

Cheers and Blessings
Faustino