How to Pasteurise Mushroom Substrate (5 Easiest Methods)

in this video we cover how to pasteurize substrate and we also look at the five easiest methods [Music] hey and welcome to this video i'll look into five of the easiest methods of cold water pasteurization now it's important let's start off by looking at the difference between sterilization and pasteurization that's a choice you've got to make lots of growers hope to sterilize their substrate and some growers or to pasteurize their substrate in short the difference is that with sterilization you try you kill all microorganisms whereas with pasteurization you opt to knock out most of those microorganisms i'll link to a separate video here if you want to explore this further lots of growers who pasteurize the substrate use hot water or steam even that's quite energy intensive here at the farm we prefer to use cold water sterilization big pasteurization rather because it's just it uses less energy less equipment and it can be fairly easy to do as well so let's look at the five easiest ways to cold pasteurize your substrate okay so we're going to be talking about these five different methods but i want to start by just demonstrating one of those methods for you so you can see what it looks like and we're going to be looking at the cold water lime pasteurization technique this works basically by raising the ph of the water solution that you soak your substrate in and when you have a high ph solution it kills off most of the competing organisms on your substrate so that the following day when you drain it off what you're left with is a clean substrate that you can then add your spawn to this is one of my favorite methods it's what we use on the farm here it works really really well it's easy and it gives really good yields as well so what you need for this method then are just a few simple bits of equipment you need some kind of container for your water and obviously you need to size this according to whatever scale you're working with as eric mentioned earlier we use a large ibc for larger batches but if you're doing this at home you can use anything like a bucket or a food storage bin like we have here today and you could use anything really from that scale upwards like a bathtub or a larger container to that we're going to be adding water and you don't want to fill it right the way to the top because it will spill out you want to fill it 60 full with water and of course you're going to want your substrate to soak in it so what we have here is some chopped straw inside of a netted bag and the type of substrate you use really depends on what you have available to you we like to work a lot with straw and you can use any type of cereal straw for this you can also use sugar cane bad gas you can even use sawdust or wood pellets if you do use those you just need to make sure when you drain them that enough water is pressed out that your heart your substrate is not over hydrated for more information on substrates check out our video we've got a whole video on different types of substrates if you want more info on that so aside from your substrate and your barrel filled with water you're going to want the hydrated lime itself now hydrated lime is calcium hydroxide it's often sold as build as lime and you want to make sure that it just is has not got too much magnesium content which most varieties don't have but some that are made from dolomite for example have too much magnesium which will stunt the growth of your mushrooms and when i say too much magnesium we want less than five percent quantity of magnesium so have a good look for that just also make sure you don't use agricultural lime or garden lime that's a different type of lime you want hydrated lime we're also going to want a ph meter just to double check that the ph is up high enough once we've added the lime to the water and you'll see that i'm wearing gloves here and that's because hydrated lime can be irritating to the skin so you want to have a set of gloves on for that and later on when i add that to the water i'll also put a respirator on just so i'm not breathing in any of the particles so when it comes to the quantity of hydrated lime you need to use you need 0.2 percent of the quantity of water so that works out to be 2 grams for every liter of water that you're using and then you just scale it up accordingly so i'm going to go on now and do the demonstration and we'll come back and talk about the next steps after that [Music] so so you should get a ph of between 11 and 13 and as you can see here we've got on the high end of that 13 so we're ready to dunk our straw and you'll find if it's straw that it will float so you're going to need a weight of some sort just to weigh it down and submerge it fully under water so once you've got your straw soaking in the lime water solution you're going to need to leave it in there for 16 to 20 hours we normally do this in the afternoon and just drain it the following morning that enables it enough time to pasteurize and to hydrate the straw at the same time and you need to drain it for at least an hour then just to let all the water run off of the straw so that it's not over hydrated and in terms of discharging the waste wastewater solution that you're left with there if you're connected to main sewage in most parts of the world you can just discharge it straight into main sewage however if you do want to neutralize it first you can use something like ph down it's just a liquid solution you add to the water that will bring the ph back down to neutral and discharge it then at that point once your straw has been draining for an hour so at that point you've got a nice clean substrate and you're ready to go ahead and inoculate and by the way i know that some people may have reservations about working with chemicals as part of their operation but i think it's important to point out that you know you can neutralize the water before you discharge it and that goes for some of the other methods eric will mention and likewise both the line bath method and the other methods that we'll discuss in a minute these are all permitted under usda organic certification so that showed you step by step how you can go about using the lime bath technique but that's not the only option open to you when it comes to cold water pasteurization you can also use ash and ash works in a very similar way to lime in the sense that it raises the ph to such a level that most organisms simply die off ash also has an advantage at least to really beautiful fruiting bodies but the disadvantage with ash is that you're limited in typically limited in quantities so if you want to grow on a larger scale it can be really difficult to source enough ash to use of that scale right then the next one is you can use soap actually soap is a really friendly material to use of course so you might prefer to use this instead of ash or lime the way this works is that it uses osmotic pressure to break down the cell walls in the micro organisms so they basically rupture and then die off the next option open to you is chlorine you can use bleach or you can use swimming pool chlorine and that kills off lots of all organisms basically and it gases off as well so there's no risk to the actual product the actual mushrooms at the end so that's another option open to you and then the final method and i'm kind of excited about that because we've seen it in use in the online course community that we support but we haven't used it ourselves and that method is vinegar vinegar is the actual opposite of using wood ash or lime in that it creates a very low ph environment which is also not very friendly to microorganisms and they die off in that way so i'm excited to try that and that trial starts today here at the fire so the results of these tests with vinegar will obviously share with our online course community and the people in that community from today onwards will also find in detail lessons on the other methods that i just described so i find this a fascinating subject matter and i'm not the only one there's some really detailed studies out there that you can look up and let's have a look at one of them done by a friend it's co-authored by a friend of ours dr john holliday in the state states who's an absolute pioneer when it comes to cold water pasteurization methods let's have a look at this report i'll link to it below this video but let's have a look at some of the conclusions of that report so the first graph i wanted to look at from the study here with you is the the one on your screen right now and what you can see here is the treatment comparison in terms of steam pasteurization lime bleach and washing powder and you can see there's a few things you can take away from this graph so on the left there's biological efficiency which is a unit measure of your yield basically and what you can see is that chopped straw which is in the green has significantly better yields than unchopped which is in the brown there on your screen and then on average lime treatment had better results than steam treatment and you can see that the bleach and washing powder methods all have a slightly lower yield so next up let's look at some comparisons within the methods i'm going to look at lime and bleach with you and what you can see on your screen now is that some strains work better with one method than others so what you're seeing is ax and elm both are oyster mushrooms and on the left there's still the biological efficiency of course and with bleach comparison you can see the difference in yield is not big at all in fact it's similar at a hundred and twenty percent however when you look on the right and you look at the lime comparison there's a clear clear difference and the elm oyster has got a way higher yield than the ax so that proves that some strains work better with one method than others so these are obviously the results of just one study and what i would take away from it is that it does actually impact the variety and the growing method does have an impact on your yields and the best way to go about this is to just take this conclusion away and run your own trials use different varieties and use different methods to see what works best in your situation so if you enjoyed this and you want to learn more check out our full workshop which i'll link to below the video thanks a lot for watching and do subscribe to the channel you

Channel: GroCycle

Views: 77,162

Keywords: Growing mushrooms, mushroom farming, mushroom substrate, pasteurize, pasteurization, sterilize, sterilization, hydrate, hydration, bleach, cold water, lime bath, wood ash, soap, chlorine, steam, hot water, vinegar, hydrated lime, substrate, inoculation, low tech, non sterile, high pH

Id: fVlJ3zND3PQ

Length: 10min 45sec (645 seconds)

Published: Fri Jul 30 2021