Why decant a bigger yeast starter?

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AnonyBrew

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I've read in here if you build a larger yeast starter, say about 2 liters, that the liquid (beer) in the starter should be mostly decanted & discarded prior to pitching the slurry from the bottom. I read that this is due to the bad taste of the beer in a bigger starter.

If you used extra light DME to make your starter in the first place why bother decanting the liquid? Especially if my target OGs are usually low from expected.

What makes the beer from the starter "taste bad"? The same DME is used in many recipes so why would it adversely affect the taste of your batch?

The reason I ask this question is that after using small starters for the past 3 batches & pitching the whole thing I had great results with quick starting & vigorous fermentations.

Most recently I used a bigger starter and decanted a majority of the liquid off the top and pitched the slurry and my fermentation seems very weak this time compared to what I'm used to seeing. I've lightly swirled the fermenter a couple of times to try & get more activity over the past few days. I wonder if it would have taken off better had I not decanted the beer from the 2L starter and pitched the whole thing.
 

Yooper

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The reason you would decant the spent wort is actually pretty simple- usually it's oxidized and without hops, so it tastes really bad. If you had alot of bad tasting stuff to your beer, you'd have the risk of having your beer taste bad.

Not decanting wouldn't make a difference in the amount of fermentation you're seeing, unless you dumped off a lot of the yeast, too.
 

jmiracle

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I never sure how to decant and I get nervous that I'm pouring yeast down the drain, so I just dump it all in...I've never had a problem but I wouldn't mind hearing if there's a "trick" to decanting or if I'm just paranoid.
 

TheDom

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I'd make sure you chill the starter for a bit before pitching in order to encourage more of the yeast to flocculate out of solution, so you're losing less when you decant off that extra wort. If you're really worried about it, you could always spend extra time/hops on the starter as a mini-brew copy of the beer you're planning on pitching it to.
 

Kaiser

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I guess there are 2 schools of thought for starters:

* pitch the starter
* pitch only the sediment

When you pitch the starter, you will have to make sure that the starter won't alter the flavor of the beer. This generally means using light malt extract and oxygen only in the beginning. No stir plate either. Pitch the starter at high Kraeusen. I think that this would be the best way to go as it is very similar to stepping up the yeast. I'd recommend a stater size of 10% of the final volume.

What you should do is to incorporate your starter into your recipe. Basically take everything that you need for your starter (extract and water) from your recipe. By doing so you are not altering the recipe. Simply take 2 qt of your brewing liquer and 6.5 oz of extract (AG brewers will have to use less grain) and make a starter. Pitch it with yeast. Since you made the starter from the ingedients for your beer, you will still end up with the same amount of beer and you are not "dilluting" it.

If you don't do it this way, I expect most brewers are, you will end up dilluting the beer's bitternes and color a little. But no big deal.


I generally discard the stater beer because I'm trying to grow lots of yeast on a stir plate and are using left over wort from previous batches. This wort does not generally match the beer I'm planning to brew. When doing it this way you need to settle out the yeast. Fridge works well for ale yeast, but lager yeast will have to ferment out and flocculate. They are still pretty happy at 34*F which is why the fridge doesn't really settle them out.

Kai
 

Philip1993

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Soperbrew said:
If you used extra light DME to make your starter in the first place why bother decanting the liquid?
If you're like me, starters are all DME, no hops, aerated a lot, and fermented hot. Try tasting it... YUCK!
 

the_bird

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Jack said:
Or you can avoid excessive aeration of your starter and hop it like I do...
If you don't hop it, you don't have to stress about keeping it out of the light. Plus, there's still the issue of hot alcohols; maybe not an issue in March, but when you're making a starter in mid-summer and keeping it on the kitchen counter....
 

Dr_Deathweed

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Not to hijack the thread, but what about yeasts with low floculation? Would decanting it still be the best idea for this situation? (starter n00b here)
 

Philip1993

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Bottom line, I make starters for maximum yeast yield and tailor my processes to that goal. Unfortunately, that also makes for a pretty crappy tasting brew so I dump it. And we're only talking about 1-2L of 'beer'. Doesn't seem very productive to put a lot of effort into making that tiny bit of beer taste good.
 

Arneba28

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after you step your starter up getting bigger and bigger. toss it in the freezer for a few hours. but dont freeze. to decant the spent wort off just use your bottling tube. and siphon off the spent wort. no diluting your wort. all slurry and lots of yeastys!!
 

Kaiser

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There is merit in pitching the whole thing at high Kraeusen as this is the point where the yeast is most active and just keeps going.

In brewing there is a process called "doubling-up" where you fill one batch into a fermenter that is large enough to hold double or quatruple of your brew-house size. Once that batch is at high Kraeusen you add another batch and keep doing that until the fermenter is full. This way you can start out with much less yeast and a smaller brew-house. This process is known to reduce the amount of esters.

Kai
 

TexLaw

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I also decant, as I do not care for 5-10% of my beer to be a starter. As others said, my starters are all DME, and that's usually stuff I won in a raffle. I typically do not care if it's light or dark, and I ferment entirely at room temperature. I include no hops, either. What, am I going to make a half gallon batch by adding a tenth or so of an ounce of hops and boil this starter for an hour? If I am going to go through all that, I may as well just brew a whole batch.

Starters go into the fridge the night before brewday, and they come out that morning. Even if the starter liquor is a bit cloudy, nearly all the yeast settles into a cake on the bottom. When it's pitching time, I carefully decant all but enough liquor to swirl the yeast back into suspension before I dump the rest into the primary. Voila. It works even for low flocculating yeast.


TL
 

raceskier

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I've done it both ways, but moved to decanting as I tried to build up bigger starters. I've been trying a couple new wrinkles with my starters. I am boiling my 2l starters in a 3l flask. I am using DME, a couple hop pellets, (I know there is controversy on this) a little bit of Whirfloc, (I scrape a little off the edge of a tablet) the minute amount of olive oil and also a little bit of anti-foam. I boil for 10 minutes or so, cool to room temp and then refrigerate over night. The Whirfloc really settles things out. I pour off the clear wort int o a 2l flask and leave all of the sludge behind. I pressure cook this wort for 15 minutes to sterilize. I then add my sterile stir bar, pitch the yeast and close with a breathable starter. Hit the stirplate for about 36 hours at room temp. I refrigerate again and everything really falls out with clear liquid above. It is then easy to pour off the clear liquid and leave the yeast behind. I then drain off some of my wort from the new batch, add it to the yeast and hit the stirplate for a few minutes to break up the solid yeast cake. The yeast appears to start being active at this time. I then add this to the wort. Kinda complicated, but it's been working well for me.
 

Kaiser

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raceskier said:
Kinda complicated, but it's been working well for me.
If you are looking to simplify your process you know where to start ;) .

You could spend this effort on culturing yeast and make yourself independent from the yeast labs.

Kai
 

Philip1993

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Man that is a lot of work. I boil 10, cool, shake/aerate, pitch. After 3-4 days, I throw it in the fridge overnight. The morning of brew day I pull it out, decant, add about 500ml of distilled water and swirl to break it up.

raceskier said:
I've done it both ways, but moved to decanting as I tried to build up bigger starters. I've been trying a couple new wrinkles with my starters. I am boiling my 2l starters in a 3l flask. I am using DME, a couple hop pellets, (I know there is controversy on this) a little bit of Whirfloc, (I scrape a little off the edge of a tablet) the minute amount of olive oil and also a little bit of anti-foam. I boil for 10 minutes or so, cool to room temp and then refrigerate over night. The Whirfloc really settles things out. I pour off the clear wort int o a 2l flask and leave all of the sludge behind.
Am I missing something, or is all this just to yield trub free wort?
 

auto

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when using a starter, do you use the specific yeast that you will be pitching with the wort or will yeast work?
 

Professor Frink

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auto said:
when using a starter, do you use the specific yeast that you will be pitching with the wort or will yeast work?
I'm not sure what you're asking, but you need to make a starter with the yeast you will be pitching for the recipe. That way you increase the yeast number and get it into reproductive phase when you pitch it.
 

auto

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Professor Frink said:
I'm not sure what you're asking, but you need to make a starter with the yeast you will be pitching for the recipe. That way you increase the yeast number and get it into reproductive phase when you pitch it.
You understood perfectly. Thank you.:D :mug:
 

Zack

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Soperbrew

I just finished a light lager about 2 weeks ago. I made a gallon starter as per mr malty....my yeast and wort were both at the same temperature (50F)..After 5 days at 50f I pitched the whole thing into my wort....also at 50f...the starter smelled and tasted just like beer...(no nasty smell) so I didn't see a problem of decanting or not decanting..mind you though...it was a lager that fermented for 2 weeks at the same temps.....beer turned out great..
one more thing...I have to credit to this from bryan rabe...
 
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What is the general consensus for the amount of time in the fridge to get the yeast to flocculate? I am sure the answer would be dependent on the yeast lets say US-56.
 

lynwitte

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Man i just made a starter used 1lb of wheat DME for about 3 days bottled used the yeast. 2 weeks later i drank the 4 bottles i got....tasted okay (not my best brew) and there was still enough yeast/sugars to carb them.
 

Gremlyn

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I was reading through the thread and saw people commenting on oxidisation of the starter using a stir plate and that contributing to off flavours, and I have to disagree. The starter should be going for a max of 24 hours (unless stepping up) and always in growth phase, and yeast grow much better in the presence of oxygen. It's the same reason your aerate your wort before pitching. Basically, what I'm saying is that if you're doing it right, then your starter won't oxidise and contribute off flavours.

With that said, I always decant since the wort used to make the starter is generally no where close to the wort I used to make the beer, so I want to limit the impact of the dilution that would result from adding in a considerable amount of plain old low gravity starter wort.
 

Gremlyn

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I only let it go 24 hours on the stir plate, it's OK in the fridge after that for a few days without being washed and stored longer term. I generally put it in the fridge for a day or two.
 

Sebowski

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I'm not sure what you're asking, but you need to make a starter with the yeast you will be pitching for the recipe. That way you increase the yeast number and get it into reproductive phase when you pitch it.
This sounds like you are pitching yeast out of the tube along with a starter. Doesn't the starter take the place of the tube yeast?
 
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