Yeast Starters

I think the correct answer is going to be 24-36hrs after you started your starter, use it but if it's done too soon, cover well with foil and let it sit in the fridge to settle until brew day.

 

Stir plate or no stir plate? If on a stir plate, let it stir for 24 hours then turn the stirring feature off and let it sit there until you are ready to pitch. If not on a stir plate, shake intermittently until you are ready to pitch. In the future, try to aim for a lower OG....say 1.034 - 1.040 range. If you insist on knowing when it's finished, take a gravity reading.

 

If the yeast have flocculated to the bottom, carefully decant most of the liquid, leaving just enough to swirl the yeast back into suspension so that you can pour into your wort-filled fermenter.

 

I recommend that you swirl and don't shake your 1 litre starter unless your ultimate goal is a 1/2 litre starter and a 1/2 litre of yeasty wort on the floor.

 

It depends. A 1.055 starter is too much, will stress the yeasties. As koopa says, you want to be slighty under 1.040. Growing yeast have this little game they play on brewers where sometimes they produce a nice krausen and sometimes they hide it. My Heady yeast had a magnificent krausen but you may have equal success with little to no krausen. Oh yeah, you should be measuring your DME by weight, not volume.

You will have CO2 off-gassing if your yeast are multiplying. Every shake should produce a thick CO2 head and a nice aroma. When shaking doesn't produce any more off-gassing the yeast are done. If you used O2 and yeast nutrient it will go quicker. I would let the yeast tell me when they're done, but not go one minute less than 48 hours . . . then chill/decant.

I get the idea you aren't keen on researching, but these two articles from Mr. Malty will give you solid knowledge on the subject.

 

your starter will be fine for Sunday. it will be fine for next Sunday for that matter. once they floc and go dormant under chilled conditions your starter does become less and less effective over time. but your cell count is (in theory) way beyond what you started with.

for homebrewers sometimes good enough is just fine. doesn't need to be ideal always.
Cheers.

 

I've done that, but I use the running from the sparge during brewday. I wait until the wort is coming out at about 1.035 or so and take a pint. I boil this pint, cool it, then add to the decanted starter. By the time you are done boiling and cooling, the starter is taking off again.

 

Not necessary. And I've never seen anything objective to suggest it helps make better beer. You'll see people say that it must be a good idea, because it "wakes up" the yeast. To which I say... okay... so....?

 

it stands to reason that if the yeast are acclimated to the wort temperature prior to pitching they will be ready to begin fermentation sooner. they are also actively fermenting when being pitched. reducing any lag between sweet wort and making beer is desirable. so there is that.
but I for one don't sweat things like this, as the extra step could just as well be argued is another thing to go wrong. we aren't commercial brewers.
Cheers.

 

It also stands to reason that introducing your full (pre-fermentation) complement of yeast into a small amount of wort will acclimate them to a different fermentation environment than the one they will be going into in another hour or so. One of the things yeast do in the lag phase is sense where they are (i.e. the environment), and how much food there is. The amount of propagation prior to fermentation will be different. Why get them acclimated only to pull the rug out from under them, so to speak. It's like... "just kidding, stop eating and multiply some more."

Both arguments are based on sound reasoning. But as I said, I've seen no objective evidence that one consideration outweighs the other.

Are there commercial brewers who add their yeast to a small amount of wort shortly before pitching into the main batch? If so, I wonder if there is some data out there somewhere.

 

It does not seem that anybody commented about starter size. When making a simple starter (no stir plate) it is prudent to make a starter larger than 1 liter. A starter size like 2 liters is more prudent (with a wort of 1.040). The rule of thumb for a simple starter is that a 2 liter starter will double the amount of yeast (e.g., 100 billion pack will grow to 200 billion yeast cells).

I personally prefer to pitch my yeast starters while the yeast is active to mitigate lag time. A longer lag time due to pitching ‘sleeping’ yeast is not necessarily a bad thing but IMO a shorter lag time is beneficial.

Cheers!

 

That's a pretty good rule of thumb, as long as you're starting with something pretty close to 100B cells. But if you're starting with significantly less or more, the doubling rule fails. And of course, if you want some final number other than double your starting count, it doesn't apply. There are calculators out there to take away most of the guesswork.

 

I don't know about that. I was trying to imply that as home brewers we do not need to always do the state of the art, the proven best, the most up to date research etc. I think this debate is interesting, but in reality it doesn't seem to make much difference to us. (I could go on about obsessing over Mr. Malty's calculator recommendations...)
Cheers.

 

What some would call obsessing, others would call reasonable attention to an easy process control. Just sayin'
FWIW, I don't (usually) use Mr. Malty. But I do use a yeast starter calculator.

 

This is addressed in Yeast. Overpitching (100+B in 200ml of wort) results in poor yeast health. The yeast cell membrane and beer profile are adversely affected. Overpitching will reduce the lag time, but this is overall a disadvantage. Those little guys need the time to adapt and having them weakened then re-introduced into a different wort is not the way to go. The details are on pages 66-69.

To expand on this: the key to yeast growth is inoculation rate, i.e. how many cells pitched per volume of wort. Zainasheff/White plotted growth rate based on inoculation rate. Of course it's influenced by agitation, oxygen, temp, and nutrients, but the optimal inoc rate is the range of 40 -125 millions of cells/ml of wort. Pitching outside of this range isn't fatal, just expect reduced results. When you go to the extreme limits of inoc rate (100+B/200ml) you get virtually zero growth (and weakened cells).

If anyone is still reading after all those numbers, this is easily handled by using a yeast calculator. It's in the fine print on yeastcalculator and brewersfriend (Brewcipher I don't know). If you input sometime really off the wall it will tell you that you're max'ed out and to try again. It's common to need multi-step starters to keep optimum growth rates which these calcs easily walk you through. Seems like software like Beersmith is readily accepted but many tend to resist these simple yeast calculators.