This tek is GREAT for most Straw Loving mushrooms!
The Tek assumes the grower is familiar with grain spawn production, because
building a 36” log, which we will be doing in this Tek, requires from 4 to 6
quarts of colonized rye or corn. If you’re using smaller than quart (.9 liter)
jars of colonized spawn, you’ll have to do the math to figure how many to use.
More spawn is better, as fast colonization of straw is essential. The
pasteurization process doesn’t kill all the contaminants; it only renders them
harmless for approximately two weeks. If the mycelium hasn’t colonized the
substrate by then, contamination naturally will occur. The pasteurization
process also spares the ‘good bacteria’ which help the mycelium to naturally
fruit better, as well as to help fight off contaminants. If
one were to put
straw into a pressure cooker and sterilize it, harvests would be much lower as a
result of killing these beneficial bacteria, and it would be considerably more
susceptible to contamination. I’ve worked hard to put together what I think is
the most concise and easy to follow directions for pasteurizing small amounts of
straw on the net today. Pictures accompany every step. Don’t cut corners, and
you’ll be guaranteed success. I’ve tried to shrink the pictures as much as
possible without sacrificing detail, to make downloads faster. I would recommend
the reader print a copy of the Tek for future use.
1) Ok, the first step is to get a bale of straw from the local co-op or feed
store. If you can find organic straw, it is preferable, because any contaminant
or pesticide that is in the straw is likely to end up in the fruit bodies. The
feed stores in my area carry organic barley straw and it works great. I know
that wheat straw would also work.
2) Using whatever tools are at your disposal, chop the straw into 1-3 inch
lengths. This is
VERY important. The mycelium simply doesn’t like to colonize straw if it can’t
get inside the hollow interior of the stems. Consider any length of straw longer
than your pinky finger as too long. It’s a pain in the neck, but don’t cut
corners here. Your project will fail.
3) Once the straw is cut, put it in a Sterlite or Rubbermaid container (or
anything else similar, like a clean trash can) and cover it completely with hot
tap water. I use the sink sprayer, to wet the straw evenly as the container
fills. When you have enough water in the tub, place a screen and weight over the
straw to push it down under the water. It needs to ‘pre-soak’ like this for at
least an hour, but not longer than 2 hours. This is to hydrate the straw.
4) During the time the straw is hydrating, you need to get the pasteurization
bath ready. You will need a container large enough to hold 14-16 gallons of
water, plus the straw. Place one Sterlite or Rubbermaid container inside another
for the insulation properties the dead air space between them provides. A very
large insulated ice chest would also work well for this. The idea is that you
want to hold the temperature of the pasteurization bath for an hour and a half.
Without insulation of some sort, the bath will cool off before the time is up
and not be effective.
Don’t start this process until the straw is soaking, or
else the pasteurization bath will be ready before the straw is hydrated, and
either you put the straw in too soon, while it’s still dry, or the water cools
off too much waiting on the straw. What you want is to have a temperature of
140F-160F, after you put the wet straw into the hot water bath. I’ve found
the best way to do this is to heat up six gallons of water on the stove until it
boils. The two pots you see in the picture add up to six gallons between them.
When you have six gallons of water on the stove boiling, place two gallons of
plain hot tap water into the clean tub, before pouring the six gallons of
boiling water into it. Immediately place the two lids on the container to hold
the heat in. Refill the pots with another six gallons of water and set them on
the stove to boil. When this water boils, it will make 14 gallons total so far.
Just before pouring in the second batch of boiling water, it’s a good time to
add the lime. Use ½ cup of hydrated lime for this recipe which uses 14-16
gallons of water. Be sure to stir the lime into the water very well. If you’re
making a larger or smaller batch, adjust the lime accordingly. This will give
the water a ph of 12-13 before the straw is added. This radical swing in ph,
along with the heat will render the contaminants inactive for a couple of weeks.
5) Once you’ve added the second batch of water, it’s
time to put the wet straw into the pasteurization bath. At this time, the
temperature of the bath will be around 180F, but as soon as you add the wet
straw, it will cool it down to the proper range of 140F-160F. Simply use your
hands to lift the straw out of the bath, let it drain briefly, then place it in
the pasteurization tub.
Once all the straw is in the bath, stir it around gently to lift any lime that
has settled on the bottom of the tub. Place a screen (hardware cloth works
great) over the straw, and put whatever object you have handy on top to keep the
straw submerged. Don’t worry about a few floaters that escape the screen. They
will pasteurize just fine floating on the surface. You don’t want to mash it all
the way to the bottom or pack the straw tight while in the bath, because you
want the hot water to be able to circulate throughout the straw during
Now, put the double lid on the tub to hold the heat in, and leave it alone while
you go clean up all the mess you just made. Make a note of the time. Check on it
after 45 minutes, and if the temp is approaching 140F, go ahead and add a couple
more gallons of boiling water to bring the temp back up. Don’t worry about
adding more lime. After an hour and a half, it’s done. Don’t go more than an
hour and a half either, or you’ll kill too much of the ‘good bacteria’.
6) Ok, it’s been an hour and a half and it’s time to take the straw out of the
pasteurization bath. Place the screen that was holding the straw submerged into
the bottom of a clean tub, and transfer the straw to this new tub to drain/cool.
Cooling will take an hour or more. Don’t waste all your hard work, by spawning
hot straw. It will kill the mycelium. Leave the lid off the tub so air can get
to it, and if it’s cool outside, take it there. Don’t worry about contaminants
landing on your straw; Millions of them will, but with the high ph of the straw,
they won’t be able to grow for at least two weeks, and your log will be pinning
by then anyway. By that time the mycelium will be strong enough to fight off all
7) Now that your straw has cooled to room temperature, it’s time to move it from
the screen it’s been draining on, to a clean tub for spawning. (You DID wash the
pasteurization tubs while the straw cooled didn’t you?) Don’t squeeze it out or
anything. The water that drains naturally while the straw cools will leave it at
the right moisture content for spawning. At this time, cut your tubing to the
appropriate length. We’re making a 36” log, so cut it 18” longer than that.
Tie a knot in one end of the tube, and using a sharp kitchen knife, poke a few
small holes in the plastic near the knot. These holes are to let the air escape
as you pack the log. Take the 4-5 quarts of colonized grain or corn you have so
carefully incubated, and beat them against a car tire to loosen up the kernels
so they can be poured out into the tub of straw. I like to start with 2 quarts
right on top of the straw.
Mix it into the top two to four inches only, before loading this top layer of
spawned straw into your tube. Add another quart of spawn and mix it in, and
continue the process until you reach the bottom of the tub, and your log is
built. It seems to work better to thoroughly mix the spawn into the straw, as
opposed to making a layer of straw, followed by a layer of spawn. This next part
is VERY IMPORTANT. As you fill your log with straw, hold the straw in your hand,
and gently sprinkle it down into the tubing, making sure it spreads evenly. You
want big clumps of straw, with air cavities between them. After each
handful or two of straw, stop and pack it down really tight with your hand.
Hold the tubing in one hand and pull up, while you stick the other hand down the
tube and push down on the straw with all your might. I weigh close to 200 lbs.,
and I push down on the straw as hard as I can. It’s very important that the
straw is packed tightly into the tube. The mycelium can’t colonize across large
air gaps, so spread the straw out evenly, and push it down really good. Don’t
stand on it or use mechanical means to get it tighter. Just push as hard as you
can with your hands, and that will be perfect.
8) Now that you’ve filled up your tubing to within 9 inches of the top, it’s
time to tie the second knot, sealing the log. Push the straw down really tight,
and squeeze the neck of the tubing against the straw. Holding the tubing with
one hand, spin the log around with the other to wrap up the plastic tubing so
you can tie a knot in it. Just make sure you tie the knot right against the
straw, so the tubing keeps the straw tight. Now lay the finished (almost) log on
the floor, and with both hands, roll it gently back and forth, to even up the
surface. Roll it like a piece of dough, to get it very smooth on the outside
) This is an important step to help achieve full colonization. Now, carefully
take your log, and place it on the shelf you are going to incubate it on. Leave
it alone for 3-5 hours, but not longer than 8 hours before doing this next step.
9) Almost done. Your log has been sitting for 3-5 hours now, so the moisture
content has had a chance to equalize. All that packing during filling had pushed
your moisture to the bottom of the bag. Some excess water may have run out the
small slits you cut in the bottom of the tubing while you packed. That is good.
Now, for the mycelium to colonize the straw, it needs
a small amount of air
exchange. It doesn’t need a lot of air, just some. Also, you want to keep as
much of the CO2 inside the log as you can during colonization. I use a hunting
arrowhead to punch holes into the tubing. You can just as easily use a sharp
knife, or box cutter. Cut slits in a + shape about every 2 to 3 inches all along
and around the log. The slits only need to be half an inch or so long. Just make
sure no place on the log is more than 3” from a vent. The idea is to have a
small amount of air exchange, while maintaining moisture content. Now, put your
log into its final fruiting location, and don’t touch it again until you see
pins forming invitro. This will be in two to three weeks. The growing mycelium
HATES to be handled, so resist the temptation to pick up your log, or otherwise
disturb it. Let it be exposed to normal room lighting during colonization, and
don’t let the temps get too high. Room temperature is fine. With a marking
pen, record the date and strain on the end of the log.
10) It’s day fifteen, and you have pins! You’ve noticed for a few days already,
that you had full colonization. It’s time to birth your log. Try to do this
without moving or disturbing the log in any way. Use sharp clean scissors to
carefully cut the knots off both ends of the log. You’ll have to cut a circle
around the knot to get it off. You can’t cut the whole knot off in one snip,
because it’s up against your log, and you’d bruise the mycelium. Once the knots
are cut off, carefully cut the tubing lengthwise along the top edge of the log,
trying not to touch the mycelium with the scissors. Peel the plastic down and
away from the log, exposing the entire surface to air, then gently and loosely
fold it back into place. There should be lots of air gaps around the log now.
fold the plastic back, then immediately replace it. This will stimulate a
massive pinning. You can cut another length of tubing to go over the top of the
log where the seam is, to keep it from drying out. Be sure to cut lots and lots
of holes in this plastic. All you want to do is slow down the rate of
evaporation, so you don’t have to mist. You do want lots of constant air
exchange. If you see a great deal of condensation forming on the plastic
sheeting, make the holes a bit bigger. As your log fruits, the mushrooms will
push the plastic away from the log as they grow. Don’t worry about the fruits
being in contact with the plastic. It won’t hurt or bruise them. They’ll love
the humidity, and you’ll love not having to constantly mist.
Happy Mushroom Growing!