Yeast-nutrition and fruiction

We are all experts on yeast, it’s what makes beer after all.
Mashematics stock a range of nutrients but the question is: are they required ?
Answer is: No.
Assuming your yeast is viable you really only need chuck it in and let it go. All grain wort has just about everything in the way of nutrients that yeasts needs, you don’t have to add anything, you don’t even need to aerate.
But you can do a lot better, you can help your friend yeast produce a much better, more consistent beer by optimising conditions.
All grain wort contains adequate amounts of everything yeast needs except for Zinc and Oxygen.
Oxygen is an easy one, yeast needs oxygen during its growth stages, the process is complex but essentially for yeast to continue budding it requires sterols, which the yeast can synthesise but not without oxygen. Thus oxygen becomes a limiting factor in fermentation, a well oxygenated wort (8-10ppm) will reach a lower terminal gravity and in a faster time than a less than adequately aerated wort.
Splashing and shaking is certainly a good start but oxygen levels are typically 3ppm at best. Pure oxygen, injected through a sintered stone will oxygenate 20 litres of wort to the 8-10ppm range in about 60 seconds.It would appear that too much oxygen is merely a waste, so 90 or 120 seconds is not deadly.
Zinc is important in reproduction of yeasts and is a co-factor for alcohol dehydrogenase (the enzyme that creates alcohol).
It is important that the zinc is available to the yeast and this can achieved by the use of Servomyces Servomyces Spec Sheet.
If you are using dried yeasts another very important factor is proper rehydration of the dried yeast.
Once again, not rehydrating is not going to hurt, its just giving less than optimal conditions.
First concept reydration is nothing like making a starter.
Temperature, always important in fermentation is critical in yeast rehydration.
In the first few minutes the as yet not properly constituted yeast wall will allow toxins such as hop compounds and even high sugar levels to pass through reducing overall viability so water is a good start anyway.
You need to pitch your dried at about 1:10 (yeast to water) in standard tap water, if you are worried about chlorination then boil and cool.
The temperature will vary according to strain, it could be as low as 30-35C or as high as 42-45C but 40C is just about right, the critical period is less than a minute after pitching which is when the yeast starts reconstituting its cell wall structure, lower temperatures will drastically reduce yeast viability, at 24C you will have 75% viability compared to 40C.
It gets better.
When you are rehydrating your yeast you can further optimise your fermentation by adding agents such as GoFerm Evolution GoFerm Spec .

So, you have oxygenated your wort, if using active dry yeast properly rehydrated with GoFerm for good luck, do you need additional nutrients, clearly NO you do not.
Which is why Mashematics carries a range of nutrients…what you don’t need is often what you miss.