Disclaimer; I am brewing predominantly ginger beer, and experimenting with some commercial yeasts in pitching.

My batches of ginger beer are 1~2 gallons max, as it's consumed pretty quickly and I turnover the bottles/bug about once per month... sometimes twice. Up until now I've been using my homegrown ginger bug w/ naturally occurring yeast in my environment but I'd like to boost them a bit and try some commercial yeasts from a local home brew store.

When looking at the yeast packet, it recommends 11.2g yeast per 20~30 liters of liquid. I did the math and came up with 1 gallon = 3.785 liters, so that means I should be using 2.12g of yeast per gallon, but that seems like a lot since my bug is good, but not great.

I'm just trying to boost the carbonation levels per batch and thinking 1g yeast in addition to my bug should be adequate, but how to measure for a single gram? I tried using my kitchen scale (which is supposed to measure in 1g increments) but could not get it to register just one gram. I'm afraid to eyeball it as I want to have a basis for feedback per batch as to how much yeast was too little/too much and/or adversely affecting flavor.

  • 1
    "I'm just trying to boost the carbonation levels..." - is this not more likely to be an issue with sugar content than yeast quantity?
    – Frazbro
    Commented Dec 18, 2018 at 3:21
  • I thought so as well Frazbro, but my latest batch from last week with the commercial yeast confirms that my naturally collected bug yeast wasn't quite enough. I kept everything in my recipe identical from the pre-commercial pitching and only added 1g of a dry ale yeast. The results were astoundingly improved! Perfect carbonation and, in fact; I had to burp the bottles a few times before I chilled them in the fridge to slow the yeasties production. They're still carbonating as I can see a bubble rise from time to time, but the contents and flavor profile are definitely improved.
    – jc allen
    Commented Dec 18, 2018 at 19:58
  • 1
    Interesting! Were you getting full attenuation with your wild ones? I wonder if they're pressure sensitive.
    – Frazbro
    Commented Dec 19, 2018 at 20:25
  • I'm certain i was not achieving full attenuation... at least with every batch. I guess the wild yeasties were a bit more finicky to variations in ambient temp, residual sugars, etc. Some batches with wild would be excellent with good carbonation and lasting the entirety of the bottle where others (later versions) were just plain flat. It bubbles vigorously when left out on the counter for a few days after a refresh and feeding with new water/sugar. Honestly, the commercial yeast feels like cheating!
    – jc allen
    Commented Dec 20, 2018 at 0:11

2 Answers 2


If your bug is already doing the job all right, then your worst enemy - underpitching - cannot get you. You also do not want to overpitch, to avoid changes in taste. Thus you have options as follows:

  1. Use amount that does not register on your scales and hope it is under 1 gram.
  2. Buy Jeweler's Scale with precision of 0.01g - available under $20. Scales with 0.1g precision are not significantly cheaper, so I wouldn't consider them.
  3. According to this site

    Instant yeast: 1 teaspoon = 3.1 grams; 1 gram = 0.32 (1/3) teaspoon

    You do not need to be exact, so this may be good enough for you.

  4. You can take 10g of yeast, add it to water to get 100g of solution. Use 10g of solution.

  • Good info and I'll look into the smaller resolution scales; thanks!
    – jc allen
    Commented Dec 14, 2018 at 14:04

Your scale may be capable of 1g increments but just not starting from zero. Place something on the scale first that puts you in the middle of the scales reported range of operation. Then weigh out 1 extra gram of yeast. For instance put a can of soup or cup of water on the scale then balance whatever you were going to measure your yeast into on top of that. Measure one additional gram with the yeast.

This only works if your scale can indeed weigh in 1 gram increments. Otherwise you need a scale designed for weights at the low end.

  • I tried this method on my batch yesterday and could not get just the yeast to trip the scale at 1g... I placed a shot glass on the scale and slowly added the yeast until the packet was empty, with no change of the scale's gradation. I have a new scale with finer resolution OTW...
    – jc allen
    Commented Dec 18, 2018 at 20:00

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