Stepping up a Yeast Starter

October 27,2010 by 52 Comments

Stepping up a yeast starter is useful in homebrewing if you need to make a big starter with a limited container size. Instead of making one huge starter in a large volume of wort, you can go in steps with smaller volumes to reach the right amount of cells.

This video shows the starter volumes and yeast quantities that you need to do stepped starters. I recreated part of a table from the book Yeast, by Jamil Zainascheff and Chris White. You should pick up a copy because it shows you how yeast can improve your beer, and unlike questionable advice based on theory, it’s based on real life experiments. We’re talking lab coats and microscopes people.

Stepped Yeast Starter Resources for Homebrewers

These two BillyBrew posts should be read before watching this video:

Here is the book Yeast by Jamil Zainascheff and Chris White. It’s really great.

And here is the table that I recreated from the book, published with Jamil’s permission:

Stepping Up a Yeast Starter Table

Click to open large version in a new window

Please note that this study was done with no added oxygen. Adding oxygen with a stir plate or by shaking will roughly double the amount of growth you get. Also keep in mind that fresh yeast was used in the study, so if your yeast is older then you won’t get as much growth.

To find the maximum size starter you can make with a given container size, read the last number in that column. For example, the maximum starter size you can make in a 2L starter is 300 billion cells (with no aeration).

Any question/comments about stepping up starters? Is that the most exciting PowerPoint presentation you’ve ever seen?

About Billy Broas

He is the founder of The Homebrew Academy, a BJCP beer judge, and the homebrewing expert on the Rocky Mountain PBS television show Colorado Brews. He lives in the fine beer town of Denver, Colorado.

52 responses to “Stepping up a Yeast Starter”

  1. Brad says:

    Great videos, Billy. I always enjoy them. The question I have about making starters comes when using washed yeast to pitch into your starter. When you wash your yeast you end up with yeast settled out in the bottom of your jar that you pitch into your starter. Well, how many cells are in that 1/16″ sediment, or 1/4″ sediment? I enjoy the idea of washing my yeast to save money but I never have confidence in how much yeast I’m pitching into my starter when I use washed yeast. Any hints, tips?


  2. Billy Broas says:

    @Brad Thanks for the kind words Brad. That’s a really good question and I’m sure a common one. I admit I’ve been very imprecise about this in the past, typically treating one of my mason jars of washed yeast the same as one White Labs vial. Yea, a bad assumption, but as long as I make a starter I’ve been confident enough.

    Since the book has made me more anal about yeast, I’ve been looking more into this. The answer is actually on the pitching rate calculator.

    If you go to the calculator at there is a tab called “Repitching from Slurry.” It’s confusing looking at first, but there are instructions here:

    Basically, it lets you estimate your yeast concentration in a slurry, and then tells you how many milliliters you need to pitch for a given batch of beer. So if you’re like me and you store your washed yeast in pint mason jars and you know you need 100 ml of slurry, that would be ~ 20% of the mason jar filled with yeast slurry. The book actually has a page or two on this very topic and gets more in depth about how to estimate concentrations.

    Thanks for asking this. It’s a relevant question and since I have the videos on yeast washing and starters, it might be a good topic for another post.

  3. Brad says:


    The only thing is that what we have as yeast in the bottom of our jars is NOT slurry, it’s washed yeast. The way I understand all this is that slurry is yeast and trub from the bottom of a fermenter. I’ve taken 2 cups of slurry out of the bottom of a fermenter and pitched that into wort and had awesome action quickly. It’s like pitching your wort onto a yeast cake, only a much smaller amount. So, Jamil’s calculator for “repitching from slurry” I don’t think answers our question about how much yeast is in the bottom of our washed-yeast-jars.

  4. Billy Broas says:

    @Brad If you’re confident that the washed yeast is100% pure then I think all you would do is slide that bottom scale all the way to the left to tell it that the non-yeast percentage is 0%.

  5. James says:

    If I needed even more yeast but constrained to my 2L flask, could I pour half the yeast into a sanitized jar and grow the starter once again?
    Specifically, say I’m brewing a barleywine and I need 450B cells. I start with one vial in my starter and double to 200B. Decant, add more wort, and it grows to 300B. Now as you said, it can’t go much bigger. But if you pour half of this into a sanitized jar and store in the refrigerator, you are left with 150B. Then you can double to 300B. Combine that with the 150B in the fridge, and you got 450 billion cells.
    Will this work or is there a limit to how much a single yeast population can grow? I imagine the main concern would be maintaining an unmutated strain of yeast and keeping viability in storage.

  6. Billy Broas says:

    @James What you said make sense to me. I think the main risk is the possibility of infection with transferring your yeast to another container. I don’t think that there is a limit to how many times they can divide, although I suspect you may be right about the strain mutating. Afraid I don’t have much knowledge in that area of their biology. Also, will you be using a stir-plate? That will result in much more growth. Jamil’s experiments were made with without one. I need to go back and add that.

  7. Randy Simmons says:

    Awesome !! That video makes it SO MUCH EASIER TO UNDERSTAND !!
    THANK YOU !!

  8. James says:

    Yes I will be using a stir plate. Do you know how much added growth I could expect?

  9. Jim says:

    Nice video and a wonderful chart. I wonder if you might be able to add one line to it. Is there a max yield in a given volume of starter wort? For example, is 150 billion cells the maximum amount of yeast you can expect from a 1L starter or 300 billion from a 2L starter. That line would be a great reference to let homebrewers know what is the minimum size starter that will be necessary, even if you step it up.

    thank again for all of your good information.

  10. Billy Broas says:

    @James I wish the book had this same data showing with and without a stir plate, but it only gives the non-stirred information. The best clue I found was a sentence about stir plates where they say it can create 2-3X as much growth as a non-stirred starter. I’d go on the conservative end to make sure you have enough, but safe to say that the extra oxygen really helps out.

    @Jim I think I get what you’re saying. I’ll go back and add a note in the post showing how to read the maximum yield you can get. Glad you liked the video and chart. Thanks for the comment.

  11. Jakub says:

    Hello, rookie brewer here. Thanks for that video it was very helpful and i will certainly be getting that book. I had a question. I read somewhere that if you happen to store your starter in the fridge after it’s done it’s thing, you can take it out the morning of the brew and add a bit of fresh wort. Let it sit for the day (outside the fridge) and the yeast should be active by the time you’re ready to pitch. Any thoughts on that? How much fresh wort would one use (i currently have a 2 liter starter made with 2 vials = 300B cells (in theory)). I don’t want any more cells I don’t think, but the idea of getting the yeast doing it’s thing again before pitching seems attractive. Any help welcome :) Thanks.

  12. Billy Broas says:

    @Jakub I’ve definitely heard of that method but have never tried it myself. It seems like a good idea though. The yeast would wake up from their slumber and hit the ground running when you pitch them into your beer. The obvious drawback is that you need to make some fresh wort. Pretty sure I heard that Jamil makes a bunch ahead of time and then cans it – probably not something most of us are going to do. The other thing you could do if you’re an all-grain brewer is take your mash running (towards the end when they’re lower in gravity), cool it down, and add that to the yeast. It wouldn’t give you a huge head start but it would help.

    As far as how much, I’m really not sure but I don’t think it would take much. Maybe 1-2 cups for your 2L starter? Don’t think the book mentions this technique specifically but I’ll check and let you know if they give recommendations. Good question and thanks for commenting!

    • Jeff Sieck says:

      Billy — that is very similar to how wine makers pitch their yeast, and it’s what I do (sort of). I actually take the first runnings from my plate chiller into an erlenmeyer and pitch the yeast into that. Then, while the rest of the wert is chilling, I aerate the wort in the erlenmeyer for 10 minutes or so and then pitch right into the fermenter. I have yet to have an under-attenuated beer (of course I’m generally using pretty fresh yeast). The main times that I use a starter are in my higher gravity beers (like a saison) where I don’t want to buy three vials…


      • Billy Broas says:

        Hey Jeff, I think that is a good idea. Getting the yeast going prior to pitching should help get fermentation started earlier.

        Also, I saw your comment on the yeast washing post and was actually going to reference you to my first comment in this post. The answer is in there. Let me know if you still have questions, cheers!

  13. erik says:

    hey billy, great videos! i am going to be doing my first starter and had a quick timeline question for you. the plan is to use a 2l starter and one vial for 300b of cells. now it seems that with a regular starter it’s not such a big deal: make the starter, wait the 24 hours or so and then pitch. but if i’m going to step it up, then it seems that i’ll need maybe 12 hours to chill (is it really ok to leave this in the fridge with just the foil on top?), then decant, then make the second starter and pour it over the yeast cake, then another 24 hours until ready to pitch (not planning to decant the second wort so not factoring in a second chill period). so do these times look about right? trying to plan my brew day and as i haven’t done this before i’m not sure if these times should be adjusted either up or down. also, if you see some error in this technique.

    thanks a ton for the feedback. keep up the good work!


    • Bill says:

      Hi Billy,
      Brilliant couple of vids on yeast starter and stepping up. Thank you for doing those, I’ve trawled the net for ages trying to find some info on yeast starters that was simple to understand, and you’ve done it! – I will be searching out a copy of “yeast” too. I’m about to do my first brew in the new gear that I’ve been building. First brew is going to be an American Amber at 1.052 OG. Thing is…. it’s going to be 100 litres (26.4 US gal) Mr Malty tells me that I need 961 billion yeast cells and the step up table doesn’t go past an 8 litre starter. What I was wondering was if I did a 2 litre starter with one vile of yeast on a stir plate to hopefully give me 300 – 400 billion cells and then repitched that into 20 litres (5 gals) of a simple starter, would that give me enough yeast for my Amber Ale? Could I get away with a smaller second starter than 20 litres? And as it would be a simple starter, how long would I have to leave it before there were enough cells? 24 hrs or let it brew out for a few days?
      Hope this all makes sense and you can help,

      • Billy Broas says:

        Bill – I think I can help you out with your dilemma. So assuming you made your 2L starter with a stir plate and have 400 billion cells, you should be able to able to pitch that into only 7 liters if you add oxygen. The chart gives you 500 billion cells without oxygen, so with it you should be able to almost double that which should give you the 961 billion cells you need. That’s probably too big for your stir plate so you’d have to shake to add O2 with a tank and stone. If you didn’t add any oxygen, the chart says you’ll need 28 liters for 950 billion cells and 32 liters for 1000. Hope that helps. That’s a lot of homebrew!

        • Bill says:

          Thank you for that Billy, thats great! Yes it’s a heap of beer – I sometimes wonder what I’ve got myself into! It’s more than just me though who’s involved in this, so there won’t be any shortage of interested recipiants. Have found a copy of yeast so will have my own copy soon too. Again, many thanks and keep up the great work!


    • Billy Broas says:

      Hey Erik, my apologies for being late to reply. Sometimes I miss the emails. I assume you brewed already so how did it work out for you? I’d say your schedule looks pretty good to me. If anything I would wait more than 12 hrs to chill. I’ve just found that it takes longer than that for all the yeast to drop and the starter to clear, but 12 is much better than 1-2 hrs. Hope it worked out for you.

  14. erik says:

    hey thanks for the reply billy. yes, i did brew and even though i’ve been doing it for a while this time was my first with a starter. bigger beer and didnt want to chance just throwing a vial in there… anyhow, think that i’ve got the timeline nailed down pretty well but it is a fairly important issue for me as i only see my beer on weekends and have to have the GF babysit it during the week. needless to say, there is a bit of planning involved.

    anyhow, thanks again!

    • Billy Broas says:

      Good to hear it worked out for you. I know exactly what you mean by the timeline being important. When you’re making starters, and especially when you’re stepping them up, it’s not like you can just wake up and decide to brew. It takes planning ahead. Glad the video could help. Cheers!

  15. Brandon Einhorn says:

    Your articles and video have been extremely helpful to me and answered some of my questions.
    I am now going to get the Yeast book.

    Thank you for taking the time to present this material.

    • Billy Broas says:

      It’s great to hear when these posts help people. Thanks for the comment Brandon and happy brewing!

  16. Landon says:

    Good video. Love the clip art.

  17. Hoptomology says:

    Great video Billy!
    I just finished reading the Yeast book myself and loved it as well. I’m starting to get into the yeast aspect of brewing more, and this video helped me get my head around stepping up and making starters. I look forward seeing what impact it has on my beers. Thanks!

    • Billy Broas says:

      Paying more attention to fermentation and yeast has made the biggest improvement in my beers. I’m sure you’ll experience the same thing. Cheers!

      • Hoptomology says:

        So I’ve heard. I’ve also almost finished building my temperature controller box that I will use on an old chest freezer to get my fermentation temps steady. My beer has been very enjoyable thus far, so if it gets even better, I’ll be in heaven! haha
        Thanks again for a ll the great articles and videos, been enjoying them…

  18. Kevin says:

    i was curious about the actual process of making the stepped starter.. if you only have a 2L flask like you mentioned, how can you pitch the decanted yeast into a new flask? would it be just as effective if after you decant the “beer” off of the yeast in the flask, to boil your new DME, let it cool, then pour that over top of the yeast in the original 2L flask?

    • Billy Broas says:

      Your last sentence is right on. If I’m stepping up in a 2L flask, I’ll decant the beer, make the new wort in a pot, and then pour that cooled wort on top of the yeast cake in the flask.

  19. David says:

    Thanks for the clear explanation in the video. I was just wondering if cold crashing between steps is necessary if you have a large container. Would I get fewer yeast if I made a 1-vial 1.5L starter, then added 2L to that, rather than making a 1.5L starter, cold crashing, and then pitching into 3.5L fresh wort? Thanks again.

    • Billy Broas says:

      Hey David.

      Well the volumes don’t match up in the two examples (3.5L vs 5L), unless there’s a point there I’m missing. To simplify, I think you’re asking if you could for example do a 1L starter, then add another 1L to the container after fermentation, as opposed to doing 1L, decanting, adding another 1L. That sound right?

      Hmmm good question. It’d probably work. It’s essentially what you do when you add priming sugar at bottling.

      • David says:

        Hey Billy, thank you for the response. You interpreted my question correctly, even though I explained it incorrectly. The guy at my LHBS said that the cold crashing is preferable so that you can get the yeast out of the alcohol, which stresses them out. However, your response about the priming sugar made me wonder if you could possibly grow the yeast in 2L of 1.04 gravity, then 36 hours later, add say 200ml with enough sugar to bring the gravity of the whole 2.2L mixture back up to 1.04. Besides the alcohol and yeast waste, would that be approximately the same as cold crashing a 2L starter, decanting, and adding another ~2L starter? If this was possible, then you could step up without cold crashing or needing a larger container, which is probably too good to be true. Thanks again.

        • Billy Broas says:

          I certainly think you could add fresh wort and get new cell growth, but the alcohol factor is a good point. When bottle conditioning you don’t really care what happens to the yeast as long as they carb the bottle, whereas you want the healthiest yeast possible going into fermentation. I’d say that technique would work just fine, but it’d be optimal to decant and add fresh wort. Would love to hear about your results though.

  20. Settled yeast sludge is somewhere in the ballpark of 8 bil.cells/mL right?
    Is it practical to run through the stepping process multiple times?
    I.e. If I made a starter of 1.040 gravity at a half gallon, and then chilled the starter to settle the yeast.
    Then, if I went through the whole process again, could I avoid buying multiple yeast packets, or would this allow for too many mutations?
    Is there a better way to prepare yeast for the trials of a full lagering fermentation in a beer that has a S.G. > 1.100 .

    Thanks for your help.

    • Billy Broas says:

      I think that concentration is too high. Mr. Malty says that the White Lab vials are 4.5 bil/ml and that’s packed in there tight. Read this:

      I’m not quite following your question. If you give an example using the chart and instructions in the video I’ll be better able to help you out.

  21. IPAsRule says:

    Hey Billy, thanks for the video. If you already answered this before I apologize. How long do you wait after pitching your first vile in your starter before decanting and then stepping up with more wort?


    • Billy Broas says:

      I wait until the starter clears so I know that most of the yeast has settled to the bottom. It normally takes 1-2 days and then I decant. I’ll wait longer if I have the time though.

  22. Ryan says:

    Hey Billy,

    Great video! Thanks for doing that. I’ve been struggling with FG of my beer and meads for a while. I finally isolated it to low yeast counts, and poor yeast handling. I started making a starter, but still had issues. I didn’t fully grasp the concept. I just threw it all in a 1 litre jar, and waited…no shaking after the initial aeration…oops…of course the yeasties weren’t happy.

    A few days ago I picked up a stir plate, and an o2 bottle. That should solve a lot of issues. But, I still wasn’t sure about the numbers…I had no idea how large a starter to make for ales, and lagers, and how to step up. This video really cleared it up (also a big thanks to the book/tables – I will be picking up that book asap!)

    Have a great day!

    • Billy Broas says:

      Hey Ryan, you’re not alone. I had a lot of problems with my beers until I took at close look at fermentation. Sounds like you’re on the right track now with the stir plate and O2. It will make a huge difference. Enjoy the book. Cheers!

      • Ryan says:

        Hey Billy,

        I have a question about that chart. If I am using a stir plate, and put 1 pack into 1 litre, the chart shows I’ll get 150 billion back. since I’m using the plate, that should be 300 billion, right? Mr Malty says I need 380 billion for the lager I want to make.

        so, I have 300 billion…or the equivalent of 3 vials…Looking at the chart, I see what’ll happen if I pitch 3 vials into 3 litres…but I don’t have a 3 litre container. I only have a 2litre one. There isn’t an option for that. So, does that mean it isn’t recommended to repitch into a 2 litre? Will it negatively affect the yeast? Or am I missing something…? Thanks!

        • Billy Broas says:

          I always need to drink my coffee before looking at this chart…

          I think the reason you don’t see a “3 in 2” cell is because you would get very little growth. It’s the diminishing returns thing. But if you give all that yeast more food, say 3 liters of it, you suddenly get much more growth. Given that you need 380 cells and “2 in 2” gives you 300 billion, and “3 in 3” gives you 450billion, I’m confident that “3 in 2” will give you enough cells, especially since you’re using a stir plate. I say go for it.

  23. Rick says:

    Hey Billy, Great Info!! I have a question, I am planning a 12 gallon batch of beer with a OG of 1.084. I have a 5000ml flask and did a starter of 3500 mil at 1.040 and pitched 3 viles of yeast and did intermitten shaking because my stir plate is broken. According to the chart, it would seem I now have 450 billion cells, Mr. Malty says I need 700 billion cells. Can I achieve that with 1 more step up? Or will I need to step it up multiple times?



  24. Jason says:

    This is a phenomenal resource for someone looking to make their first yeast starter. Very simple to understand. Thank you for creating it.

  25. TimD says:

    Great video, thanks for posting. Looks like I may have been underpitching my beers, even with making starters. Time to step-up my starter game.

  26. JustinFam says:

    I thought I have read that you should step up yeast in increments of at least 5-10x the amount of wort from the previous steps…? Is this correct? The way I interpret that is if I made a 1 liter starter, I should then make at least a 5-10liter starter after that, which makes very little sense to me. Do you have any clarity on that issue?

  27. Mike says:

    Hi Billy,

    Thank for the article! So if I’m understanding this correctly, you’re estimating 150 Billion cells from a 1 Liter starter with no oxygen and no stir plate?

  28. James says:

    Hey Billy,
    I am relatively new to yeast starters. I used to just make a starter per instructions with my starter kit but am trying to really understand what I am doing and why. Basically, that last batch I made came out horrible and I know it was low yeast cell count. I decided to make a yeast starter based on the usual instructions I had and after doing some research, which is how I found your video, there is no way this yeast starter will be enough. So, I put in my numbers in the mrmalty calculator and it says I need about 1.5 liter starter. The starter I made is only 500ml. I was thinking about stepping it up so my questions is, After I decant this liquid can I make another 1 liter of wort to put on top of this? or do I need to stick with just the 500ml?

  29. Gary Griffin says:


    I have a question about the table and how big a starter can be made. For a 2L starter where you say the max size is 300B cells, is that a “stepped up” starter or a one time starter

  30. Zach says:

    I have a similar question as James, I think. My Beersmith 2 software suggests using a 2.1L starter for my beer I am about to brew. I only have a 2L erlenmeyer flask, though. If I make a 1L starter, ferment it, decant it, and then re-pitch the yeast into another 1L starter, is that the same as a 2 Litre starter? I would think it would be but I would understand that maybe you somehow lose fermentation efficiency throughout 2 steps

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