I've wondered about this for a while: most 'how to make a yeast starter' instructions I've seen suggest using only the yeast-rich sludge, and tossing most of the starter medium.

This makes sense if the yeast won't be used right away, in which case it also makes sense to 'wash' it before tucking it in the fridge. It might also make sense if, for the sake of purism, you want to minimize the amount of extract in an all-grain brew.

Otherwise, as long as the starter is fresh and active (and you've allowed for the volume in determining your hopping rate), I don't see any reason not to throw the whole thing in.


4 Answers 4


It is recommended to decant and dispose of the starter beer because the starter beer is nasty and oxidized, nasty and devoid of fermentable sugar by the time the yeast have reproduced to pitching levels. "You would not brew a beer with this level of oxidation, so why would blend it into your beer?", goes the thinking.

  • Why would it be nasty? Why would it be oxidized? I don't think mine are either of those. I dump it all in (usually it's only about 300 ml in a 20 liter batch).
    – Jeff Roe
    Commented Aug 29, 2014 at 4:49
  • 1
    If it's that little, go ahead if you can't taste it. But that small a starter isn't usually a good idea. Mine are 2-3 qt. and I certainly don't want that in my beer.
    – Denny Conn
    Commented Aug 29, 2014 at 15:10
  • 1
    I have saved some of the decanted wort in a qt jar, just to taste the difference when I first keg it (before carb).
    – Wyrmwood
    Commented Sep 2, 2014 at 22:45

In many cases, the starter beer is simply going to be diluting the wort, and not necessarily in a compatible way. The starter beer is probably not the same color, malt make up, hop profile, &c. as related to the beer. Plus, as ChinoBrews mentions, if properly aerated, the starter beer is likely to be oxidized.

For the requisite starter volume for most ale batch sizes, the ratio of starter beer to fresh wort is low enough that you're just not going to notice. For the larger pitch rate and thus starter volume requirements for Brett or lager starters, the starter beer starts (heh) to become an appreciable fraction of the overall wort volume … 4L of starter for a 20L batch is 20% of the total volume.

Personally, I usually try to cool and decant starters before pitching, but if it's just 1.5L into a 20L moderately-hopped 1.030 OG batch of saison, maybe I don't care quite so much.

  • Thanks, jsled and Chino Brews, that makes sense. Btw, it's not that I'm too cheap to toss the 'overs,' it just struck me as a waste if their presence is unlikely to affect the finished beer (for the worse, of course).
    – Glasseyed
    Commented Aug 28, 2014 at 22:47

We usually toss the entire starter in our batches of beer and we haven't noticed any detectable off flavors from doing so. It's probably better to decant but I haven't noticed any difference.


Here I'll list potential issues and give my assessment of whether they are real (based on 1.5 l starter made of pale malt or light DME, and 20 l batch).

  • Body/ABV will change because of potential dilution. Not really: say, the starter is made to be of 1.040 OG. The average beer is 1.050 AG. The dilution is negligible.

  • IBU will change because of dilution. Not really. The calculated IBU might change, say, from 30 to 27, but whether the change in bitterness will be perceived, I doubt.

  • Different sort of malt used for starter will change the beer taste. Not really: it's just 0.3-0.5 kg of base malt used for starter.

  • Beer will degrade because of oxidized starter. Not really. First, you're aerating the batch before pitching the starter, anyway. Second, what some beer flavour stability experts say (recently heard that in Beersmith podcast), active yeast will clean up those oxidation byproducts, and you're certain to get some yeast activity.

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