Explaining the method of dunking your cakes in water and then rolling them in vermiculite to improve your flushes
Why Dunk and Roll?
Mushrooms are basically 90% water. Dunking and rolling will increase your yields dramatically with hardly any work. You are essentially replacing the water lost by the cakes and allowing them to produce more fruits. Normally the water runs out way before the nutrients in the cake do, so as long as you are replenishing the water the substrate will keep on producing fruits for at least a few more flushes.
When Should I Dunk and Roll?
Immediately after birthing a cake and before placing it in the fruiting chamber you should always dunk and roll. A lot of water has been lost during the weeks the substrate has been colonizing.
Between flushes. Once you have picked all the fruits off the cake or none have been growing for a few days you know your flush is over. Now is the time to dunk again, preparing the substrate for the next flush.
The procedure is divided in two parts:
In this step you will be replacing the water lost by the substrate.
Rinse off your cakes under the tap, rubbing them softly do dislodge any loose material or bits of mushroom material left over from picking the fruits. Be careful not to break off any pins (little immature mushrooms) as they will be your next crop. Pins will survive the dunk and roll no problem, so no need to take them off. Just be delicate with them.
Submerge the cakes under cold tap water for 12-24h inside a clean container. Try and avoid dunking for much longer than 24h but the closer you get the better as cakes are very dense and need a long time to absorb all the water . You can use the pan you sterilized you cakes in, a clean tupperware container a bucket, whatever is available. You will notice that the cakes actually bob about like corks so you will need to put something heavy ontop to keep them fully submerged. This is important as it seems that the extra bit of water pressure that comes from being totally submerged aids the rehydration process.
There is no need to dunk inside a fridge. As long as your water stays cool (below 40ºF) you will be fine. The cool temperatures of the fridge prevent bacterial bloom while you are dunking (it has nothing to do with cold shocking the mycelium, as this procedure is not required for Psilocybe Cubensis) but unless you are pretty clean your fridge probably harbors a lot of contaminants, so it can be counterproductive. Use ice, running water (can be costly) or the fridge to keep your water below 40ºF.
Once your dunk has finished, re-rinse your cakes under the tap and proceed to...
Rolling your cakes increases the water holding capabilities of the cake. It essentially acts as a mini casing layer.
Roll your cakes in dry vermiculite so they are evenly coated with it. You can optionally bake your vermiculite in the oven for an hour at 350ºF if you think it might not be clean (the bag has been opened for a long time for example) but it is not necessary if the vermiculite is out of a new bag.
Place the cakes inside your fruiting chamber (not in direct contact with the perlite, use a circle of foil or an old jar lid as a coaster) and wait for an hour or so.
Mist your cakes thorougly making sure you wet all the vermiculite.
Maintain fruiting conditions as usual.
While dunking between flushes is a must, re-rolling between flushes is optional. You will see that the mycelium colonizes the vermiculite slightly so it does not all come off during the succesive dunkings. There is no need to get it all off. Either do not re-roll, just patch up the bald areas or roll again. Whatever looks best to you.
Letting the cake dry out between flushes. By not misting for a few days after the flush has finished and then dunking you are imitating the natural cycle of drying out followed by sudden rehydration. In nature this rehydration will stimulate rapid fruit formation. Also, the drying out protects your cakes from molds during the waiting period as the drier surface is not as prone to contamination.
Extra vermiculite reservoir: Put a spoonful of vermiculite on the top of the cake when you place it in the fruiting chamber. Once wetted when you mist, it will act as an extra water reservoir.
Try and create a good microclimate. By dunking and rolling all your cakes and packing them close together you will be creating a microclimate among your cakes where humidity is at its max. This is an invaluable aid for good flushes. These pictures show how well dunked and rolled cakes can perform.
Nibin 2009. Special thanks to Fahtster for the images and monstermitch for his thread on dunk and rolling