yeast starter questions (from me)

First of I know there are many threads on starters around but they are actually causing more of a problem than providing me with answers. Basically there are a lot of conflicting views out there.

Hence, this thread. Where I'm hoping to get specific answers to my questions.

I'd like to make a starter with some 1056 that i washed may 1st. I want to use this starter in a 1.074 ipa I am brewing this weekend.

1) How big? - How much of a starter should i make. How to brew talks about 2 cups of water to 1/2 cup dme. I read others upward of 3L (for lagers). How much wort should i make for this starter?

2) How much yeast? I've got 5, 250ml mason jars with washed yeast in them . There is really only about 1/4 inch of sediment in the bottom of each. How many of the jars should i pitch?

3) How long? - I've read to prepare the starter from 12 hrs to 7 days before.

4)Airlock or just foil? - I've got a 1G jug to store the starter in. I've read airlocks aren't good. Should i just cover it with foil?

Thanks for yer answers.

1. http://www.mrmalty.com/calc/calc.html The problem with this is it gets a bit tricky with washed yeast. I use 1L of water for every 3oz of DME. When someone says 3L starter, they're usually referring to the total amount needed. In that case, you would start off with a 1L starter as normal. You'd let it ferment out, then decant the liquid off of the yeast that's compacted at the bottom. Then you'd cook up another 1L batch of wort and add it to the slurry you have. Do this again until you hit 3L of total wort used. This will continue to build up yeast.

The thickness of your washed yeast slurry will really determine how much you need to make. I'd go with a 3L batch just to be safe. You'll need around 150ml of yeast total. Not the liquid on top of the yeast...straight yeast.

2. You really only need one, but the less yeast you start with, the longer it'll take you to build up a good starter.

3. All depends on how much activity you get from them. To be safe, I'd start it tomorrow and wait to brew until Sunday.

4. I use an airlock and have never had problems.

Hope this helps.

Suthrncomfrt1884 said:

1. http://www.mrmalty.com/calc/calc.html The problem with this is it gets a bit tricky with washed yeast. I use 1L of water for every 3oz of DME. This will continue to build up yeast.

The thickness of your washed yeast slurry will really determine how much you need to make. I'd go with a 3L batch just to be safe. You'll need around 150ml of yeast total. Not the liquid on top of the yeast...straight yeast.

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I have looked at the pitching calculator and I've been confused by the slurry. When i enter in 6G ale at 1.074 from yeast washed May 1st it says I need ~600ml of yeast. Is this at the end of my starter when i decant the wort off the top? I ask because you say 150ml.

When someone says 3L starter, they're usually referring to the total amount needed. In that case, you would start off with a 1L starter as normal. You'd let it ferment out, then decant the liquid off of the yeast that's compacted at the bottom. Then you'd cook up another 1L batch of wort and add it to the slurry you have. Do this again until you hit 3L of total wort used.

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Just to be clear do I only pitch yeast into this starter once? Not every time I add another L of wort, right?

I didn't realize it was 6 gallons and harvested on may first. That makes a huge difference. 600ml may be right. I'll double check later today when I get off work.

And yes, you only pitch yeast once.

A yeast starter theoretically requires plenty of oxygen. The yeast will consume sugars and produce alcohol without the presence of oxygen but, as far as I know, they need oxygen in order to multiply.

I usually just cover it with cling wrap or foil, and remove periodically to help circulate oxygen, as well as frothing it up with a bamix. Works for me. If using an airlock works for you, then do it

ballzac said:

A yeast starter theoretically requires plenty of oxygen. The yeast will consume sugars and produce alcohol without the presence of oxygen but, as far as I know, they need oxygen in order to multiply.

I usually just cover it with cling wrap or foil, and remove periodically to help circulate oxygen, as well as frothing it up with a bamix. Works for me. If using an airlock works for you, then do it

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To circulate the oxygen should i just remove the airlock/ foil and give it a swirl every couple of hrs?

Yeah, that sounds good. If you have a watertight container, you can shake it to aerate it really well too. Because carbon dioxide is heavier than air, I feel that you need to get the air moving with, say, a hand fan to get oxygen in there after it's already produce some CO2. I don't think diffusion will be enough.

I have just been looking at john palmer: http://www.howtobrew.com/section1/chapter6-5.html

He says that the initial aeration is enough. He also says to keep air out after this, but doesn't give a reason. I have found that I get more yeast more quickly if I aerate regularly, and have never had an infected started or anything. I think the large population of yeast in there would prevent anything else taking hold.

You can also use an airstone to constantly pump oxygen through the starter if you want to get technical. Like everything else in brewing, you can do things really, really precisely and get really good results, or you can wack some wort in a jar with some yeast and hope for the best, and...you'll still probably get great results

With the slurry being almost two months old, the viability will probably be somewhere around 60% (assuming 25% loss/month). Assuming it's about 90% yeast by volume to begin with, that gives:

4.5*0.9*0.6 = 2.4 billion cells per mL, give or take. So 40 mL (a little less than 3 Tbsp) of yeast will be roughly equivalent to a fresh smack pack, and you can just pretend that it is for the purposes of using the MrMalty calculator.

For a 1.074 ale using "intermittent shaking", that would require a 2.2 L starter. With a slurry this old, it might not be a bad idea to make a 500 mL "wake up" starter first, then pitch that into 1.5 L once it ferments out. Otherwise you'll probably have a long lag time, which could give any nasties in the wort time to start reproducing. Either way I would plan for a full week to give yourself time to chill it down in the fridge and decant the starter "beer".

I would definitely recommend against using an airlock. Loosely cover the starter in foil, and shake it as often as possible. Access to oxygen is the biggest determining factor in how much yeast a starter will grow: Aeration and Yeast Starters

a10t2 said:

For a 1.074 ale using "intermittent shaking", that would require a 2.2 L starter. With a slurry this old, it might not be a bad idea to make a 500 mL "wake up" starter first, then pitch that into 1.5 L once it ferments out. Otherwise you'll probably have a long lag time, which could give any nasties in the wort time to start reproducing. Either way I would plan for a full week to give yourself time to chill it down in the fridge and decant the starter "beer".[/URL]

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Helpful post, thanks!

I'm still new to starters so i just need to clarify a couple things.

Last night I boiled 1L water and added 3 oz of dme. Would this equate to your "wake up" starter? Once that ferments out I will add another 1.5L. When do I move it from room temp to the fridge?

TacoGuthrie said:

Last night I boiled 1L water and added 3 oz of dme. Would this equate to your "wake up" starter? Once that ferments out I will add another 1.5L. When do I move it from room temp to the fridge?

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1 L is a little bigger than I'd like to use, but I'm sure it will work fine for you. You want to move it to the fridge once the second stage has fermented out (no more foam on the surface, yeast is settling out when not shaken up).

Did you already pitch the yeast, or has the liter of wort been sitting out overnight? If it's just sitting there I would re-boil it.

FWIW, with a 1 L first stage, your second can also be 1 L and will still get you to the cell count you need. Getting two-stage numbers out of MrMalty gets a little tricky, but it can be done: Two-Stage Starter Calculations

a10t2 said:

1 L is a little bigger than I'd like to use, but I'm sure it will work fine for you. You want to move it to the fridge once the second stage has fermented out (no more foam on the surface, yeast is settling out when not shaken up).

Did you already pitch the yeast, or has the liter of wort been sitting out overnight? If it's just sitting there I would re-boil it.

FWIW, with a 1 L first stage, your second can also be 1 L and will still get you to the cell count you need. Getting two-stage numbers out of MrMalty gets a little tricky, but it can be done: Two-Stage Starter Calculations

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I pitched two jars of washed yeast (just the slurry) into the 1L last night. I will let it ferment out and then add a second L - probably tomorrow afternoon as i'm actually travelling for work today/ tonight. Then cool and decant.

I am really hoping to brew on Sunday. Are these realistic timelines? Should I put the starter in a warm spot to increase temps?

So I am brewing today and i'm wondering if this starter will give me enough yeast?

To review: Thurs - I brewed 1L 1.040 wort and pitched the slurry from 2 jars of 1056 washed on May 1st.

Friday afternoon - Add another 1 L of wort to step up.

Lots of shaking for a few days.

Sunday morning - I put this in the fridge to cool.

Here is what it looks like right now:





I expected this to separate more like washed yeast. Is that right?

Should I just decant and pitch the slurry? I ask because according to mr malty i should pitch 600 ml of slurry and I definitely don't have that much slurry.

thoughts?

I think you probably have plenty there. If you are under-pitching, it won't be by much.

TacoGuthrie said:

Should I just decant and pitch the slurry? I ask because according to mr malty i should pitch 600 ml of slurry and I definitely don't have that much slurry.

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Yes, I would definitely decant. The MrMalty calculator is using a date about a month and a half ago, right? With fresh slurry you should need more like 75 mL.

Yes it is calculating it from a harvest date of May 1st.

This is somethign that confuses me about the calculator. I am using yeast i washed 6 weeks ago so i clicked the "Calculate viability from date" button. So should i uncheck it if I am using the yeast in a slurry I produced this week?

You want to use the date active fermentation stopped (which in a starter is probably the same as the day you pitched it). Putting in an older date means you're using yeast that was harvested on that date, not the fresh yeast from the starter.

thanks for the help in here.

I'll decant and pitch. I've got more than the 140 ml the new calculation calls for.

ballzac said:

A yeast starter theoretically requires plenty of oxygen. The yeast will consume sugars and produce alcohol without the presence of oxygen but, as far as I know, they need oxygen in order to multiply.)

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Yeast only need ATP in order to multiply. ATP is the energy source the cell uses and is created from oxidation of glucose with or without the presence of oxygen. In the presence of oxygen the yeast are able to produce significantly more ATP than in environments that are oxygen deficient.

In other words, yeast will multiply with or without oxygen but will multiply faster in the presence of oxygen.

So how does glucose oxidation occur without the presence of oxygen?


EDIT: Also, does this mean that ATP supplements could be added to give the yeast a better chance at producing more biomass? Thanks

ballzac said:

So how does glucose oxidation occur without the presence of oxygen?

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Oxidation means the loss of electrons it does not mean "use of oxygen." (I know it is really strange to use the term "oxidation" but that is what the chemists came up with. It takes some getting use to but most of my students get it with repeated use of the terms.) Aerobic means with oxygen and anaerobic means without oxygen. Oxidation of glucose or other sugars in anaerobic conditions occurs by the process of fermentation.

Aerobic conditions in the wort is very short lived. At most the yeast have about one day of oxygen. Proper pitching of lots of yeast will have the yeast use all the oxygen in a few hours. The oxygen here is not important for the multiplication of yeast in the wort through cell division. What is important is that the yeast produce compounds that the yeast will need later during fermentation. Using oxygen, yeast will form unsaturated fatty acids, which are used to make important storage compounds and cell membrane compounds. Sterols are also made with the use of oxygen and is used for cell membrane structure (Priest and Cambell, Brewing Microbiology 2002).

EDIT: Also, does this mean that ATP supplements could be added to give the yeast a better chance at producing more biomass? Thanks

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No, ATP is only a phosphate carrier. It transports this chemical energy to other parts of the cell for use. You still need the glycolysis and other chemical reactions to make other products for the use in the cell. When ATP (3 phosphates) is used it will be converted to ADP (2 phosphates) or AMP (1 phosphate). Then when ATP is produced it will use ADP and AMP to produce them.

So stick with sugars

Thanks for the detailed response

..................

You and I had a very similar question at the same time. Here is my question, and my assumptions:
https://www.homebrewtalk.com/f163/detailed-yeast-starter-questions-251490/

You're right luke!

I was doing MORE yeast research the last couple of days because i had to make a starter out a wyeast propigator pack for the first time and I read your thread.

I think we're in the same spot right now. Personally I'm comfortable with the rest of my brewing process and ingredients and I'm reallly trying to educate myself on yeast: washing, starters, pitch rate etc.

FWIW this brew from last year turned out great using my two jars of washed yeast, a 1L stepped up to a 2L starter and then decanted. However I have no way of knowing, nor did I calculate how much slurry/ how many cells were used.

Like you said in your thread, you'd like to nerd out and start doing those cell counts to get a proper pitch. I am at the same spot right now.

It seems easy w/ liquid yeast packs because there are specifically known starting cell counts, but washed yeast is a lot tougher. Plus I never did figure out how to 'step up' w/ Mr. Malty Calculator.

In the end I feel like i go round and round, researching a ton of stuff right before I brew. Then I make the starter, it works and I leave it all till next month when I brew again. Mostly because I simply don't have the time to follow up.

This is a long post saying very little...

Nice - well good luck to you. I think I've got all the info I can get at the moment, without throwing myself into it and learning "trial by fire" style. Fell off track with the Bruins, Stanley Cup Games, and drunken parades. My next few batches will all be re-used yeast...should be fun, and hopefully somewhat well calculated.