Do Worms Like Stale Beer?

Interesting question from Mark:

Occasionally, we find ourselves with an old bottle of flat beer that
has lost all it’s effervescence. Rather than just throwing away before
we recycle, I’m wondering if this old beer would be good to inoculate
some bedding material or partially dry food scraps prior to top
feeding our worms? One would think that the sugars and carbs would be
a good addition!?

Hi Mark,

What you’ve described goes against my own “leave no beer behind” moral philosophy (some might even call this a “beer crime”), but I won’t judge you for it!

Joking aside, that’s a really good question! As is often the case with me, my response would be “it depends”. Would I recommend adding a fair amount of beer to a smaller system – absolutely NOT! But I wouldn’t hesitate to empty out a small amount from the bottom of a single bottle into a larger outdoor system.

Obviously we need to remember that beer contains alcohol, which is not a worm-friendly substance. This helps to explain why things can go terribly wrong in a bin containing a lot of sugary/starchy materials that goes anaerobic (fermentation is an anaerobic pathway). But if the worms have a sizable safe zone in their habitat, a little alcohol is not going to cause any issues – and will likely evaporate or get converted into something else pretty quickly.

You are right about the carb components of the beer – those should help to boost microbe activity once the alcohol is gone.

One side-note before signing off…

If you happen to be a home-brewer, the left over spent grains (“mash”) can be a really good “food” material for vermicomposting. But you need to be REALLY careful about how much you add. It is best if you feed them in moderation, and make sure to mix up with a variety of other materials (including bedding) as well.

Hope this helps!

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    • TimJ
    • January 9, 2014

    What’s “moderate” for a VB24? I’m a pretty avid homebrewer, but I’ve bypassed the bin with my spent grains for fear of fermentation fiascos. Also, good to see a post go up; I was worried you’d abandoned your worm herd and wormheads!

    • Bentley
    • January 9, 2014

    Hi Tim,
    My recommendation is basically to test out on a very limited basis initially and then just to gradually work up from there. It all depends on your particular system (what stage it’s at etc). With a fairly new VermBin, something like spent grains could definitely trigger excessive heat-production – so that would be an example of when to be even more careful.
    Try freezing as much of the stuff as you can (unless of course you have an outdoor system it can be added to), and just start with a small handful here and there to see what the worms do with it.

    No worries about abandoning my worm-head friends! I can disappear for periods of time, but I will always be back (unless I get hit by a meteor or something – lol). Truth be told, there is actually quite a bit going on behind the scenes here! Some cool things coming your way soon – will likely write an update post tomorrow.

    • TimJ
    • January 10, 2014

    Interesting point about overheating. Like so many others, my bin is in an unheated basement and here in Massachusetts it gets pretty cold (though I’m sure you Ontarians wouldn’t be too shocked by the temps). Activity in the VB is near a standstill and I wonder if using some spent grains might help to get the temp up and the microbes moving again.

    I’ll probably be brewing in the next few weeks at some point. I could freeze some of the spent grains and then warm them up again even, to try to bring some heat back into the system and see if I can jumpstart activity in the bin.

    I used to also use worm tea in my bin, with great results and I wonder if wetting the system with microbe-laden tea might also help (given a warmer system).

    • TimJ
    • January 10, 2014

    Thinking more about beer . . . if one were so inclined, a quick cooking of the beer (a few minutes at a boil) would remove alcohol from the solution, leaving behind just the essentially sweet water (and some alpha acids from the hops). If you soaked some cardboard in this, then added it, perhaps to scraps as they thawed after freezing, along with a small innoculent of living material, I wonder if you might even further speed up the decomposition.

    Don’t waste your fancy Belgian Trappist stuff on this, but even a cheap beer is likely to work, or maybe a batch of homebrew that didn’t progress as planned . . .

    OK, no more posts to this thread for a while.

    • RonM
    • January 12, 2014

    Because my large (3x3x1.5 foot) bin is in the shade most of the day, I will occasionally add good amount of spent grains to a section of my feeding area of the bin. I add about a 2-3 cups of grain along with anywhere from 1-3 quarts of blended kitchen scraps. I sprinkle the scraps with mealworm frass and bury it a few inches below the castings. By the next day it’s is nice and warm which keeps the warms happy and hungry. By the third day, they will be munching away from the edges of the food mass until is gone. I usually do this once every few weeks. I also use spent brewery grains for making bokashi bran. I sprinkle it on the bedding to keep the beneficial micro organisms plentiful in the bin.

    Be careful storing spent grains, they start smelling REALLY BAD after a few days in a bucket. You can store them longer if you add bokashi bran, EM1, lactobacillus inoculant, or some other form of fermenting bacteria to the grains.

    • Bentley
    • January 14, 2014

    Hi Tim – some of the spent grains or coffee grounds could likely help to get the heat going a bit.

    Cool idea re: the cooked beer + cardboard. I bet the worms would love that!

    • Duane Faber
    • January 24, 2014

    The idea about stale beer led in a different direction. I remembered that I had a half gallon of old apple cider left over from Holiday celebrations that could be something to try. I had mixed up about 3 gallons of 50-50 mix of expanded wood pellets (using water) and alfalfa cubes (also soaked in water) per Bentley. Then added 1# of Purina Worm Chow to the mix. This was done around the beginning of Dec. After letting it age for a week, I added a small amount to the top of my Worm Inn. It took 48hrs. before the the worms attacked this. I didn’t realize I had so many worms. After reading about the beer, and me having the cider still around, some of the original 3 gallon mix was getting dry. So in goes the cider to wet things down, let sit for a few days and see what happens when added to the Worm Inn. Now the HMM was very good, but once the worms started on this (again took about 48hrs.) there were so many worms I could not even see the lump that I had put in. A few days later I covered half of the surface, same result. Only this time there also 100s (my guess) of small baby and juvenile worms eating away to their hearts content. Makes a person feel all warm and fuzzy. lol. What also makes this interesting is that my basement is between 58-65 F. (It is 0 degrees outside) Anyway, my fun story with HMM and a Worm Inn .

    • Mihwa
    • May 25, 2022

    If your worms are 21 yo or older, it will be fine.

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