Zinc Sulfate drops as a yeast nutrient for beer?

[Silver_Is_Money]

Food grade liquid Zinc Sulfate is sold as a dietary supplement at the concentration of 15 mg per every 10 drops (or 1.5 mg per drop). Can this product (wherein the ingredients list indicates as contents only water and zinc sulfate) be added to the fermentation vessel to provide needed zinc, and if so, how many drops should be added per gallon of wort to be fermented?

 

[dmtaylor]

I have heard of the benefits of zinc for yeast, but I have never used it for this purpose. Based on things I have heard elsewhere, I would think one single drop would be good for 5 gallons. I would be careful not to use more than 2 drops. They don't need much. Just the slightest hint of the existence of zinc is all they really need.

 

[ain]

For best performance, zinc levels should be between 0.1-0.3 mg/l, with 0.5 mg/l being maximum.
Therefore, for a 10l batch, add 7-10 drops.

LE Sorry, i've miscalculated. 7-10 drops for 100l.

 

[Silver_Is_Money]

My initial thinking is 2 drops for every 5 to 6 gallons going into the fermenter, to achieve a ballpark of ~0.15 mg/L zinc.

 

[ain]

LE: Sorry, for a 100l batch, add 7-10 drops.

 

[Silver_Is_Money]

So why add only a pinch of zinc instead of a broad spectrum yeast nutrient? In a different thread discussing a perceived dullness for beers brewed with mineralized RO or distilled water, Martin Brungard mentioned that the one thing completely lacking in RO/Distilled water which is actually needed by the yeast is a small amount of zinc, which would normally be present in virtually all natural water sources. Most if not all other needed yeast nutrients are present in abundance within the malts and grains that comprise the grist. So my thinking is to save money and add only the missing zinc.

 

[ajdelange]

The old lore is that the brewmaster threw a couple of pennies into the kettle.

 

[Silver_Is_Money]

The old lore is that the brewmaster threw a couple of pennies into the kettle.

That would work, sans that they are copper clad zinc.

 

[ajdelange]

The time period from which the lore arose I do not know. Clearly it would work with today's pennies once the copper cladding was dissolved away (you could rush that with nitric acid if desired). Prior to 1942 it would not have worked at all as there was no zinc in the penny prior to that date. Prior to 1982 there wasn't much zinc so I guess it must have been 1982 or later.

 

[Silver_Is_Money]

At 1 to 2 drops per batch (2 to 4 for 10-11 gallon) the liquid zinc sulfate dietary supplement bottle will last a long time. I think that at 10 drops they provide for 30 dietary supplement doses, so at 2 drops the bottle would last for 150 x 5-6 gallon batches of beer.