Thursday, January 6, 2011

Coffee Ground Mushroom Spawn

There is a fine line between a medium that is used for mushroom spawn (that is, to transfer to another medium) and one that is used as a growing medium. Some, like cardboard, are more structurally suited to transfer and may not have enough nutrition to take the mycelium all the way to a bountiful flush of mushrooms. Others, like straw, which is messy and difficult to fully sterilize, are more suited to fruiting and less good for production of spawn. Coffee grounds is one that is good for both. The granular nature of the grounds makes for quick and easily colonization by the mycelium. The process of making coffee out of the grounds conveniently sterilizes the growth media, limiting the opportunities for contaminants. The woody nature of the seed pod of the coffee bean also provides good woody material as well as abundant nutrition for the mycelium. Another nice feature is that most coffee filters are made of paper, which is also readily digestible by mycelium.

The first trick is to find a suitable mushroom to grow on coffee grounds. I have had great luck with both Pleurotus ostreatus (pearl oyster mushrooms) and Hypsizygus ulmarius (elm oyster mushrooms). I am currently attempting it with Agrocybe aegerita (pioppino/black poplar mushrooms), but my stem butt was small and it hasn’t made much progress yet. I suspect that there are other mushrooms that would do well in this medium as well, but not being a coffee drinker, I don’t have too much opportunity to try out new combinations. Also, I prefer to start my coffee ground cultures with stem butts from fresh mushrooms. If you are a one-pot-a-day household, this method works really well.

The method for growing mushrooms on coffee grounds is really easy. Wait until your coffee grounds are cool enough that they are no longer steaming, but not quite cold and put one pot worth of grounds, including the filter, in a bag or jar. Nestle the stem butt (or a little sawdust spawn, or whatever spawn you are using) into the center of the coffee grounds. In about two days, the spawn will recover from the transfer and will have visible signs of growth, in the form of a white, fuzzy coating. From there, you can add more coffee grounds at the rate of about one pot a day. Again, the coffee grounds should still be warm, but not warm enough to burn your hand. You add coffee grounds as the mushroom grows. If you start to get too far ahead of the mushrooms, as evidenced by a lot of uncolonized grounds in your container, stop adding for a few days until the mycelium catches up. The mycelium should more or less colonize the grounds after they have been in there just a day or two. If it takes much more than that, contamination can become a problem.

Moisture is another issue. Often coffee grounds have residual liquid in them. Mycelium can’t really colonize substrate that is under water. If I am using a gallon Ziploc bag, I will just pour the liquid out as it accumulates. In a glass jar, however, the liquid can be used for another purpose. Glass jars have less air flow than a bag that can be fully opened. When the jar is full, you can get fresh air down to the mushrooms if there is a little liquid in the bottom by just turning it upside down. As the liquid travels through, the pores in the material will be filled with air, which naturally has to be drawn from other areas. Just open the jar to get a little fresh air in the top, then turn it over and let it sit a few hours. Then turn it over again. Just don't do this before the jar is full as it will disturb the mushroom too much.

Overall, the container should be opened once a day to give the growing mushrooms a source of air. Usually this is accomplished when you open it to add the coffee grounds for the day. You can also give the mushrooms air flow by using a canning jar and replacing the sealing portion of the lid with a coffee filter (unused) or a piece of fabric.

Just keep the jar in a cool, dry location while it is growing. Once the jar is full and the mycelium has fully colonized it, as evidenced by the fact that it is all cottony-white and no longer smells like coffee, it can be used as spawn to transfer to another medium or it can be just fruited. To fruit it, give it another week or so to grow, and then open up the jar. Put it out in the light, but don’t put it in direct sun. Put a plastic bag over it as a tent, but punch a few holes in it for air flow. Then spray it a couple of times a day. Personally, I know a lot of people like to try to force the process, but I like to let the mushroom tell me when it is time. When, in the process of your daily airings, you see primordia, tiny baby mushrooms that look like pinheads, you will know it is time to fruit the mushrooms. You should get two or maybe three good fruitings out of a jar and maybe more out of a bucket.

Once the medium is done fruiting, you can still use it as spawn to start another kit. You can mix it with more coffee grounds, or just compost it again and start with another stem butt.

34 comments:

  1. I'm currently growing some Shaggy mane (Coprinus Comatus stem butts on cardboard. it's colonizing really fast. I'm going to add some of the cardboard spawn to my coffee grounds. Been looking for some wild Oysters to grow on my grounds but no luck lately....

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  2. Using coffee grounds is a great idea! I have been exploring new ideas in mushroom cultivation, and another thing you can do to promote faster colonization that I think was mentioned in mycelium running is to blend up the stem buts into a slurry. Every single peice that is not dead will be covered in mycellium within two days, even the ones that are practically microscopic. Depending on your slurry/media ratio you can colonize your spawn very quickly with this method. I have found that the easiest thing to do is just put a couple cups of water in the blender, blend up the stem butts in the water, and use the slurry to hydrate your media. I have only really tried this with oyster mushrooms so far though, I dont know how other species will like that kind of treatment.

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  3. I am not sure I would go so far as to put a stem butt in the blender. It sounds like you did so and it worked, so that's great, though. It has been my experience that breaking up the mycelium too much can weaken it a bit and reduce your chances of it rebounding. So I would probably only try it with healthy, vigorously growing stem butts. But if it works, it sounds like a great way to spread the mycelium! Thanks for the comment. Also, Svdharma, I checked out your blog and added it to my Google reader feed. Good stuff!

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  4. I'm just beginning to entertain the thought of growing mushrooms... but I'm a student and the thought of throwing down $25 on spawn is a little unrealistic. Do you think I'd have much luck with stem butts from grocery store mushrooms? And do you think button and cremini mushrooms would grow well on coffee grounds?

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    1. My advice, based on experience, is to buy a small pack of spawn, enough for a jar of coffee grounds, let it grow, get used to the mushrooms growth patterns, then use it to grow more once you have harvested.

      when you put half a jar of colonised coffee into a fresh jar of coffee grounds, the mushroom gets straight to work.

      Good luck

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    2. stem butts from store bought oyster mushrooms work great on cardboard

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  5. This blog is awesome! I love it!

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  6. found some oysters yesterday and can't wait to try this - hopefully I can get a mason jar of oysters fruiting for my high school biology students! I have grown shitake from plugs, but it was pricey to do. Should the jar be kept in the fridge,at room temp,or in a 60-65 degree basement? Thanks! - John In VA

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  7. John - First of all, make sure your identification is correct. If you already ate the oysters and you are okay, the stem butts are probably okay. As for growing them, they can live just fine in the fridge, but their growth will slow way down. I use the fridge to retard growth. They would do fine in the garage or in the house, though they will probably grow faster in the house.

    Honestly, though, if you are doing it for your students, I would get it started at home and then take it in. Once the cottony, ropy growth starts moving outwards from the stem butt, take it in. At that point, it won't be a dud. The growth will look different every day and your students can watch it and even help with the adding of the coffee grounds. Then you can fruit it when it is full grown.

    I like to grow mushrooms in mason jars as well and I use the regular top to keep out contamination. I just make sure to open it once a day or so to give them enough oxygen. They will be fine closed over the weekend in the classroom, it'll just slow growth. Good luck!

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  8. Thank you for sharing This article.Excellently written and lot of information we learn about it, if only all bloggers offered the same level of content as you, the internet would be a much better place.

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  9. Hi, I grow oyster mushroom and king oyster from coffee grounds. I collect the grounds from a local coffee store, put it in a clean plastic tub, add the spawn and let it go. I've had pretty good results so far (see my blog posts - http://westclifftransition.wordpress.com/2012/03/04/oy-oy/)

    I've got around 350kg of coffee grounds being colonised into mushrooms, the plan is to harvest once they are ready, then expand the substrate with more coffee. Once i have enough substrate colonised, i'm going to start using seaweed and old newspapers.

    Think about it, if you wanted to start a small business, or create a sustainable urban vertical farm, oyster mushrooms provide a cheap, effective, healthy solution.Go for it!

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  10. I've been researching this for a while but have no practical experience yet. I'm thinking of starting with butts from the ubiquitous agaricus bisporus, on a coffee ground starter, and then transfer to commercially bagged/composted manure. Do you know if this manure has any fungicides or other additives in it that would be harmful? Would I do better starting these on a grain/rice flour mixture?

    I figure that this is a good inexpensive way to experiment. What do you think of my approach to this?

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    1. I wouldn't bother with Agaricus bisporus (aka button mushrooms) it is a different kind of mushroom, a tertiary decomposer. It prefers to grow in rich soils. Commercially, they grow it on composted and pasteurized composted manure. I am not sure if it would even grow on coffee grounds. I suppose if the materials are free (you got a stem butt on your mushrooms from the store, for example) you could try it. I just prefer the primary decomposers as their substrate is much more manageable.

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  11. I wish could post more pictures so I could know if I was doing this right. How do I know if I have mycelium or mold?

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    1. I'll see if I can round up some pictures to tell the difference. The easiest way to tell is to just give it a few days. The mold mycelium turns green as the spores form. But once you see them a couple of times, you can tell the difference pretty well. Mostly. The mold is a bit spottier and random-looking, while the mushroom mycelium is denser and a little more organized looking. If that helps at all...

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  12. Great blog, thanks. I've got a start with oyster mushrooms using your coffee technique, and am moving to a larger container. Do you keep the culture in a light or dark environment?

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    1. Mushrooms need a little light to form properly. In a completely dark environment the stems elongate and the caps stay small. But enough light to read by is plenty.

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  13. Hello,

    Do you think tea grounds would work?

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    1. There are two problems with tea bags, that I have found. The first is that coffee grounds have hot water continuously poured through them, making for some pretty effective sterilization. Tea bags are typically put in water that is just below boiling and left to sit a short while as the water cools. I have noticed that tea bags tend to mold pretty quickly and contaminate my sample. Also, tea is made from leaves, while coffee is made from woody beans. The coffee beans have more dense nutrition for the mycelium.

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  14. Very nice article - I used to use coffee grounds mostly for veg gardens but have started realizing their use in mushroom cultivation. Does anyone know if the flavor of the coffee makes its way into the mushrooms? So bolder coffee gives a certain flavor?
    If you want some free coffee grounds check out projectgreenbean.com its more of a grassroots effort to recycle coffee from local coffee shops.

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  15. i have been thinking about growing mushrooms as well, and have been wondering if coffee grounds would work... thanks for the helpfull info! my question would be - does the mushrooms absorb caffine from the bean?

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  16. The quick answer to Java George and momasam is no, the mushrooms do not taste of coffee and they don't contain caffeine either.

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  17. I am thinking of using a 5 gal. bucket with coffee grounds. I would like to purchase "ready made" spawn from a reputable dealer. What is the correct ratio of grounds to spawn for this size bucket? Can you recommend any suppliers? Will they grow well on a back porch or would they grow better in the house. Thank you.

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  18. How long does the spawning process take?

    I am about to venture into mushroom growing for the first time I have bought a kit to familiarise myself with the process and wondered if I can use a part of the growing medium to cultivate my own spawn?

    Great blog and very informative

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  19. I have just started my Mushroom adventure, learning from everyone else. Thank you for this blog as it is another informative group. I have spawn started from oyster mushrooms from the local Harris Teeter in cardboard and coffee grounds which are doing well so far. My next step is the preparation of substrate for the Mushrooms to flower. I am considering tree leaves as I have a very wooded lot and I'm thinking it would be similar to dead wood needed for the shrooms to grow. Anybody tried this yet? Haven't found any information when googleing. I am considering both leaves and coffee grounds mixture as the substrate.

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  20. So that is how it is done. Looks simple. I think I can manage that.

    psilocybe cubensis syringe

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  21. It's a great way to grow mushrooms and stops all those coffee grounds being dumped into landfill sites.

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  22. Hi!
    I've just started to try this out by growing mushrooms in polythene bags. I have one doubt though. After mixing the spawn and coffee grounds, I will need to wait for a couple of weeks to allow fungi to colonize. Now, during this time, should I keep spraying them with water? I read somewhere that water is not required for initial 15-20 days. But I feel that this will cause the coffee grounds to dry completely. What should I do?

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  23. Hello!
    Thanks for the great post. You encouraged us to start the experiment, so we ordered the mycilium to start, but by mistake we ordered seeds instead of sprawns, (something similar to what appears here http://hifasdaterra.com/store/300_g_shiitake) any clue if it would work out with seeds?

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  24. I have tried the coffee ground 3 times, once with pasturization and once with sterilization. Each time I did it I got contamination. Now I have one going on newspaper but it has stalled. Should I add coffee grounds? What are the specific conditions and substrates one can make at home to get them to fruit. I have stamets books but they seem geared for the industrial and technical people. Help! I really want to succeed and havent. I think opening the bag daily also contams to enter and a tyvek filter on a canning jar over a 1/4 " hole would suffice and keep out contams.

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  25. Am I understanding this correctly, just put a mushroom with a stem in some moist coffee grounds and it will take root? Then just dump more coffee grounds on and it will grow more mushrooms

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  26. Julia - close. It needs to be a stem with healthy white, fuzzy stuff at the end of the stem. Don't use the mushroom or the stem. Just the white fuzzy stuff. Also, only some mushrooms work. Oyster mushrooms work particularly well.

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  27. hello and thank you for all the détails. i»'m missing on one thing... once you have colonized all the coffee in the bag. do you split those new spores in new coffee with light and water spraying to get mushrooms to grow or you let it all in that bag, spray water and wait for mushrooms??? thanks

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  28. Hi. I'm growing the mushrooms on coffee waste as you said, the coffee is full colonized by white mycelia but there is not fruiting body yet...why? I'm keeping T and Humidity quite well...what else can be? help! I wanna eat mushrooms
    Thanks!

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