Author Topic: Measuring gravity and stopping at the right time  (Read 12752 times)

Offline Slurk

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Re: Measuring gravity and stopping at the right time
« Reply #15 on: April 24, 2013, 09:05:26 AM »

Question: As a commercial brewer, what do you consider as the most critical phase/element/ingredient or where do you have less process control?

R, Slurk
Honestly, I have the least control over my employees. If they eff up, I have to live with the consequences. Second to that, is how the beer is stored/sold/served. I train and have specific written procedures, but at the end of the day, they're individuals and circumstances I just can't lose any sleep over.

Thanks a lot for your answer brewfun!
Many things to consider and many perspectives. And we have all seen how, from time to time, wonderfull produced beers are killed by unprofessional people down in the logistic chain.
R, Slurk
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Ready to drink: Slurk Fjellbrygg, Slurk Foeyn Ale, Slurk Agurk (Cucumber Wit), Slurk Belgian Blonde, Slurk Eng (Raspberry Wit), Slurk Hav (Seaweed Wit)
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Offline beernbourbon

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Re: Measuring gravity and stopping at the right time
« Reply #16 on: April 24, 2013, 07:59:18 PM »
The most important point of control is fermentation and yeast health. That's a topic discussed over and over on these forums with great information and depth. I have the additional task of getting 12+ generations out of my yeast, simply to control costs.

Holy cow! 12+generations??? How in the world do you do that?? I've heard of some of the guys talk about 4 or 5...... that would be so cool to get that many brews out of my yeast. The cost savings alone...... <my little calculator brain is spinnin' up> I can't imagine how much you guys spend on yeast for just one brew.
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Offline tom_hampton

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Re: Measuring gravity and stopping at the right time
« Reply #17 on: April 25, 2013, 06:54:02 PM »

Holy cow! 12+generations??? How in the world do you do that?? I've heard of some of the guys talk about 4 or 5...... that would be so cool to get that many brews out of my yeast. The cost savings alone...... <my little calculator brain is spinnin' up> I can't imagine how much you guys spend on yeast for just one brew.

Err....the same way you do 1 generation...just 12+ times.  Honestly, have you tried doing X+ generations on a homebrew scale?  I get bored of the same yeast profile after 4-5.  Besides, as homebrewers very few of us brew often enough to take advantage of the practice. 

I do it a few times a  year.  But, you have to brew back to back batches in order to do it.  It works great for good floculators.  English yeasts are perfect.  These yeasts ferment and floc out fast, so they are still nice and healthy when the beer has finished and cleared.  So, you can easily brew a series of english beers once every 7-10 days.  Ordinary Bitter, Special Bitter, ESB, IPA, Porter, Imperial Porter, etc.  Its customary to progress from low to high gravity, light to dark beer, low to high hops.  But, its not required. 

It can work for moderate floculant yeasts (CalAle, etc), too.  But, they take longer to clear, so the yeast is not quite as healthy by the time you can harvest it.  As long as you can harvest within 2 weeks...its still ok. 

Low floculant yeasts are a problem though.  Hefe, Kolsch, many belgian strains....all are low floc yeasts.  These take a long time to clear.  Usually 3-6 weeks.  By that time the yeast has been without nutrients for a LOOONG time, and is not as healthy.  You can still reuse them, but its best to revive them with a starter on a stirplate.  The other issue with low flocc yeast, is that if you try and harvest early, you end up selecting for the higher floculant cells (because the really low floc yeast is still floating in the beer).  Within 2-3 generations you won't have the same flocculation characteristics---it happens very fast. 

when it comes to those belgian strains, that are so very attenuative (and low flocculating)....a big part of their attenuation is because they don't flocculate.  That lets them hang around in suspension for a long time and chew away every last bit of fermentables.  If you make them less flocculant, by harvesting too early...they don't attenuate as much.  Now you have a yeast that won't make that dry-belgian-blond anymore.  Its still just a touch sweet. 

One of the major advantages of the homebrew scale is the total freedom to use a different yeast for every single batch.  It's complex and expensive to manage multiple strains on the professional scale.  There are lots of breweries that won't even consider two strains.   Its a very rare brewery that comes on the brewing network and states that they routine use more than 3 yeasts.   

Cost savings are ok, but if you really want to save money making homebrew....learn to make those brews that cost a crazy amount of money.  You won't ever compete on cost with the low cost stuff, and the medium cost stuff is usually a wash. 
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Offline brewfun

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Re: Measuring gravity and stopping at the right time
« Reply #18 on: April 26, 2013, 02:34:36 AM »
Holy cow! 12+generations??? How in the world do you do that?? I've heard of some of the guys talk about 4 or 5...... that would be so cool to get that many brews out of my yeast. The cost savings alone...... <my little calculator brain is spinnin' up> I can't imagine how much you guys spend on yeast for just one brew.

I have the advantage of cone bottomed fermenters that let me drop trub and harvest exactly what I want. I have the further advantage of brewing very frequently, so repitching is done within 3 to 5 days, occasionally longer. I feed every batch with yeast nutrient, which really helps the yeast performance across that many batches. Glycol lets me crash chill a beer 20 degrees in 24 hours, pretty effective at clearing most of the yeast.

As for cost, I'm about 4 hours north of White Labs. A 15bbl pitch costs about $500, delivered. I have two active strains, a lager and an ale.
Beer Appreciation is the space between pints.

Offline Slurk

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Re: Measuring gravity and stopping at the right time
« Reply #19 on: April 26, 2013, 09:01:39 AM »

Low floculant yeasts are a problem though.  Hefe, Kolsch, many belgian strains....all are low floc yeasts.  These take a long time to clear.  Usually 3-6 weeks.  By that time the yeast has been without nutrients for a LOOONG time, and is not as healthy.  You can still reuse them, but its best to revive them with a starter on a stirplate.  The other issue with low flocc yeast, is that if you try and harvest early, you end up selecting for the higher floculant cells (because the really low floc yeast is still floating in the beer).  Within 2-3 generations you won't have the same flocculation characteristics---it happens very fast. 

when it comes to those belgian strains, that are so very attenuative (and low flocculating)....a big part of their attenuation is because they don't flocculate.  That lets them hang around in suspension for a long time and chew away every last bit of fermentables.  If you make them less flocculant, by harvesting too early...they don't attenuate as much.  Now you have a yeast that won't make that dry-belgian-blond anymore.  Its still just a touch sweet.

Thanks Tom!
I had a post last week "Yeast with low flocculation. How to wash/isolate yeast from such a yeast cake?" with not that many reactions. I still had some remaining questions in my head regarding how to avoid changing the original yeast culture characteristics for low floculant yeasts. Your description (ref. quote) of low floculant yeasts gave answer to these questions :)

Regards, Slurk
 
Ad Fundum!

Ready to drink: Slurk Fjellbrygg, Slurk Foeyn Ale, Slurk Agurk (Cucumber Wit), Slurk Belgian Blonde, Slurk Eng (Raspberry Wit), Slurk Hav (Seaweed Wit)
Aging: Slurk Whirled White Wheat (Wit)
Fermenting:
Next brew: Slurk Hav

Offline grathan

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Re: Measuring gravity and stopping at the right time
« Reply #20 on: April 26, 2013, 04:37:02 PM »
Couldn't you just crash cool and collect the yeast? I just made a starter of Kolsch yeast and after 3 days in the fridge I am pretty sure most of the yeast is in the bottom.

Offline tom_hampton

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Re: Measuring gravity and stopping at the right time
« Reply #21 on: April 27, 2013, 12:16:15 PM »
Couldn't you just crash cool and collect the yeast? I just made a starter of Kolsch yeast and after 3 days in the fridge I am pretty sure most of the yeast is in the bottom.

In theory, yes.  In practice, some yeasts are very resistant to crashing.  Many of these yeasts require very low temps (28-30F) in order to actually drop out.  Not everyone can get their beer that cold....I can't.  I have a cold-room that I keep at 45F.  I do all my fermentation in this room, and store my kegs in there too.  I do not have a freezer. 

A belgian blonde that I just finished using WLP500 never did floc out.  I left it for 4 weeks.  And, I swear it was just as cloudy after 4 weeks as it was during active fermentation.  I finally kegged it with gelatin to drop the yeast. 

Kolsch yeast is not as resistant as WLP500.  But, clarifying a starter in a flask is much easier than clarifying a 5 gallon fermenter.  The inverted cone of a flask helps to restrict vertical circulation.  Plus, the starter is only a couple inches deep...not the 18-24" of a fermentation.  The deeper the vessel the longer it takes to clear. 


R.I.P.:Belgian Blonde
On Tap: Apfelwein, Kolsch(v2), Pumpkin Ale, Belgian Specialty 
Aging/Storing: Coffee Porter, Chocolate Porter, Flanders Red, English Barlywine
Fermenting: Maggie's Altbier
Next Up: PtE(1.1), Belgian Dubbel?

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Offline MikeinRH

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Re: Measuring gravity and stopping at the right time
« Reply #22 on: April 29, 2013, 06:29:52 PM »
Beerfun: Great Post!!!
I have a question as to how you maximize your generations of yeast. Do you wash after a fermentation? Or do you separate a starter?

Offline brewfun

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Re: Measuring gravity and stopping at the right time
« Reply #23 on: May 01, 2013, 09:14:57 AM »
Beerfun: Great Post!!!
I have a question as to how you maximize your generations of yeast. Do you wash after a fermentation? Or do you separate a starter?

No to both of those questions. I don't have a lab (or even space for one), either. It would be easier and more reliable, if I did. Plus I'd get at least twice as many generations. Once a fresh pitch is used, it never sees open air again. It is aseptically transferred from batch to storage and back into the next batch.

Here are my control points

A: Sanitation at every stage.
B: Most of the trub is bypassed, leaving clear wort going to the fermenter (see the pic)
C: Yeast nutrient in every batch (high zinc)
D: Harvesting the creamiest, healthiest portion of the yeast cake from the cone
E: Lots of O2
F: pH monitoring of fermentation
G: Limiting my selection to one ale and one lager strain
H: Both beer and yeast are kept at proper temperatures for their stage of the process

*pic came out sideways. Sight glass should be on the bottom and the fermenter cone is on top.
« Last Edit: May 01, 2013, 10:37:37 AM by brewfun »
Beer Appreciation is the space between pints.

Offline smiffbrewing

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Re: Measuring gravity and stopping at the right time
« Reply #24 on: May 03, 2013, 01:07:01 PM »
Take the advice of the original response. You never want to stop a fermentation. the yeast needs time to go back and clean up all the off flavors they produced during the primary fermentation. You can control the final gravity/ abv of the beer by adjusting mash temps and picking yeast strains that attenuate to the level you desire. Sounds like you need to pick up a copy of John Palmers "How to brew" and read it cover to cover.
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