Hi Jaime,

you need the dry weight of the initial substrate. Keep in mind that dry weight loses are high, so if you use the final weight, you will overestimate the BE. The problem there is how to take on account the spawn (inoculum) if you are adding seeds. If you used commercial spawn, you can just assume that it had 70% water. Let me know if I can be of further help.

best

francisco

Hi Jaime, I agree with the answer by F. Kuhar. If you are using spawn, you may prepare a little more aboundant than what you think is necessary, once prepared and mixed as homogeneously as possible, weigh it and then make a sample (sterile). Weigh the wet sample and then dry it in the oven, so that you know the percentage of water. Thien you can subtract the percentage of water from the wet weight of the spawn you've actually used.

best wishes

Thank you both for your answers! You've been very helpful Francisco Kuhar Alessandra Ricelli

You need to look at the dry weight of the substrate before starting the crop. I assume that you are preparing bulk substrate by steam pasteurization, then allowing the substrate to cool before spawning and then filling your bags for spawn run. I recommend taking ten samples of substrate after pasteurization (and before spawning). Weigh them, oven dry these samples separately, then weigh the dry samples again. Use the ten values to generate a mean dry weight. This will also tell you the moisture content of the prepared substrate. This is an important value to use to evaluate your substrate preparation. The uniformity of your ten samples also allows you to evaluate your substrate mixing process. If there is substantial variation, you will have to work on mixing to get a more uniform substrate. The dry weight, as you suggest, is necessary in determining biological efficiency of crop production. All of these are very important variables to consider when evaluating your production system - a key to improved production. Best of luck.

Dear Jaime Ahumada

Let it Assume you have 100kg of Spent Coffee grounds and you sterilized it by any method for mushroom cultivation. it will gain weight during sterilization. From this initial 100kg substrate you got 15kg mushroom in whole season.

than you got BE=(15kg/100kg)*100 = 15%

• NOTE: You should always use dry substrate for mushroom cultivation.

Francisco Kuhar Do you recommend to take the dry weight of all the bags in my experiment or is it possible to take a few bags and use the mean dry weight?

Jaime, if you have some reason to think that all bags will be normally distributed arround some weight value, you can sample some. This distribution depends on how you filled the bags in terms. did you weight the hidrated substrate? did you use some volume measure? did you fill the bags until some level?

Kujar what if I use equal weight 1kg substrates for all the bags