Zinc usage - amount for healthy fermentation

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

cactusgarrett

Supporting Member
HBT Supporter
Joined
Apr 8, 2008
Messages
2,333
Reaction score
918
Location
Madison, WI
Instead of necro'ing an almost ten year old thread, I thought I'd spin up a new one regarding zinc usage for healthy fermentation for anyone doing math for themselves.

Recent generally accepted sweet spot for elemental zinc seems to be 0.3 ppm into the fermenter (that is 0.3 mg zinc per 1 L wort). However, this gets convoluted a bit since you need to take into account your form of zinc (ex. heptahydrate, monohydrate, etc.). For this purpose, I'm examing the heptahydrate (because that's what I have on hand). There's 22.8% elemental Zn in ZnSO4*7H2O (heptahydrate), so the info in the OP of that other thread would actually yield about 0.114 ppm elemental zinc instead of what they thought was a 0.5 ppm target.

The OPs prep matches closely with what BSG recommends on the low end (0.5-1.0g per 10 HL => 0.5-1.0 ppm), translating to 0.114-0.228 ppm elemental zinc.

I crunched numbers for my own purposes (6.5 gal into fermenter) and what I'd need to prepare and perform:
  • Stock Solution: 494 mg into 100 mL water
  • Working Solution: 5.0 mL of stock solution into 6.5 gal wort => 0.228 ppm
(obligatory "show my work" and imperial/metric conversion section)
5.0 mL x 4940 mg/L x 1L/1000mL x 22.8% ÷ 6.5 gal x 1 gal/3.8 L = 0.228 mg/L (ppm)

Obviously your preferences and targets will vary.
 
Very timely post. Craft Beer and Brewing has a recent episode on fermentation health, with a deep dive on zinc at around the 21 minute mark link. I thought it was fascinating.

My main take aways:
* Cold side zinc addition is better, as studies show that 60% of hot side zinc is bound up in trub.
* Premix Zinc Sulfate in acidified RO water and autoclave (pressure canning) to sterilize; can easily make a year or two's worth of home brewing amounts in one batch.
* Barley malt has about 100ppb of zinc, so add ~200ppb to reach sweet spot of ~300ppb or .3ppm
* Dosing at the high end of the BSG recommendation seems about right: 1g/10hL
* Lagers are actually more sensitive to yeast health, so zinc dosage is more important. This may be because off flavors are more noticeable?

I have yet to add this to my process, but it's on my list.
 
Dialing in zinc is one of the biggest positive leaps you can make for beer flavor and quality. The number of pro brewers who don't do any of this is mind boggling. All good info above, but I'd add if you start doing this, target 0.3 ppm zinc for ales and 0.2 ppm for lagers. Zinc is also cumulative, so it often takes a couple generations to see full effects... so if collecting yeast, make sure to harvest when fermentation is complete and re-use within a week, ideally.

For a 1% zinc solution, 2.75 ml in 5.5 gallons is 0.3 and 1.8 ml is 0.2 ppm.
 
target 0.3 ppm zinc for ales and 0.2 ppm for lagers
I understand this changes, too, when your grainbill changes. Higher percentages of adjuncts will need higher amounts of zinc, but at that point people have recommended the use of a general nutrient that conains FAN as well as Zn when you're looking at 60% wheat, etc.

I think the end target is 0.3/0.2 ppm, but I keep hearing that 0.1 ppm is carried downstream via the malt, so it's advisable to add 0.2/0.1 ppm yourself. I don't know how much merit there is to this claim, though.
 
Check out the podcasts in the first couple of posts. Most of the zinc in the boil is bound up with proteins et al. Adding zinc to the fermentation gets it where it needs to be.
 
I have actually switched to cold side additions of yeast nutrient after listening to the Craft Beer and Brewing podcast. I’m not sure it made a huge difference, but the sulfur production is lower (I make mostly lagers). I’m not sure if it’s the nutrient or the high levels of FAN in the starter which also reduces sulfur. Flavor is mostly unchanged so far.

Without some lab work, it’s very difficult to get an accurate measure of dissolved zinc in the wort since other ingredients also contain some zinc. I just add Wyeast nutrient to the fermenter by boiling it in a cup of distilled water, cooling it and adding it before the wort and yeast.

The reason I use Wyeast is because I really don't have another good source. It takes such a small amount to hit the .3ppm level with only a 7 gallon batch, I risk over dosing. The other thing to consider, is making sure that if you make a starter, the zinc levels are up in that wort. I add a big dose of organic yeast nutrient (autolyzed yeast) to the starter to make sure the lager yeast is heathy. The organic yeast nutrient contains some zinc.
 
Last edited:
Doesn't grain contain zinc and magnesia in such amounts that adding additional amounts won't really do anything?
My understanding of the conventional wisdom is that all-malt grain bills contain all the nutrients needed, except for zinc. Wort contains some zinc, but not enough.

I'm looking at my notes, and I add 0.1 mg/L hot side for ales and 0.2 mg/L for lagers. It's been long enough that I don't remember which sources I consulted to arrive at these numbers.

I found it to be more than a bit of a hassle to find zinc compounds that were explicitly labeled as food grade. I eventually found this, which I dose using a micropipette, and so one bottle will last forever. I think I've also found food-grade zinc gluconate. Brewery suppliers do sell bulk zinc sulfate, but in unreasonably large packages.

2 ppm zinc gives better foam. Fermentation consumes virtually all available zinc, though, so zinc for foam has to be added at packaging.
 
I add Wyeast nutrient on the hot side, about 1/2 tsp for a 5 gallon batch. The ingredient list for the WY nutrient mix says it contains zinc, but I am unable to find anything online that quantifies that. Wyeast states it is a "proprietary mix."

I might order the zinc solution drops that @AlexKay linked above, and use some to bolster the zinc in the wort. Maybe 1-2 mg/L. I know that zinc can be toxic to yeast but I believe that would require a much greater amount to be a problem.
 
The penny isn’t going to dissolve, and a little copper won’t hurt. I’m just going to wire wheel a penny a little and try it. If it helps it will just be my secret weapon.
 
* Cold side zinc addition is better, as studies show that 60% of hot side zinc is bound up in trub.
Jennifer Talley's fantastic Session Beers: Brewing for Flavor and Ballance already has me adding salts, to noticeable effect,* post-mash, to make up for those that get trapped in the mash, so this makes sense.

Not having read this article and relying upon Wyeast nutrient @10min, would you suggest that the nutrient might be more usefully added as a whirlpool addition? Perhaps at ~150F? That should keep it from precipitating out with the trub, right? The mead guys just add it to the fermenter, right? I've often thought about that...why not?

Thank you, both! I'm eager to start messing around with this data!

*This isn't the same as Brungard's advice about withholding salts from your mash, later to be added. Talley is, instead, arguing that you should reinforce salts lost in your mash. Very different, and a big improvement in my ales/lagers and more in line with this discussion.
 
Last edited:
My understanding of the conventional wisdom is that all-malt grain bills contain all the nutrients needed, except for zinc. Wort contains some zinc, but not enough.

I'm looking at my notes, and I add 0.1 mg/L hot side for ales and 0.2 mg/L for lagers. It's been long enough that I don't remember which sources I consulted to arrive at these numbers.

I found it to be more than a bit of a hassle to find zinc compounds that were explicitly labeled as food grade. I eventually found this, which I dose using a micropipette, and so one bottle will last forever. I think I've also found food-grade zinc gluconate. Brewery suppliers do sell bulk zinc sulfate, but in unreasonably large packages.

2 ppm zinc gives better foam. Fermentation consumes virtually all available zinc, though, so zinc for foam has to be added at packaging.
Interesting. What is your exact dosing rate when using this product and how do you split the dose between pre and post fermentation?
 
My first post so "Hi" to everybody and thanks for the great site.
I'm on my 6-7th batch of 5gals so fairly new to this great game.
I started with Kviek. First batch was with Voss - great result. Next batch was with harvested yeast and I thought fermentation wasn't happening so pitched a new packet of lutra. In the process of taking the lid off the fermenter there were many bubbles - I now think that the re pitched yeast had been doing it's job and had blown the lid off.
Anyway I harvested and dried. All my subsequent voss/lutra brews take off within hours.
I've recently noticed that my beer is tasting a little tart and not as dry as I would like. Last batch had FG 1.014
So now looking at water chemistry and yeast vitality.
Basically from what I've read it makes sense that yeast could be in need of zinc (and maybe nitrogen), particularly if re pitched.
I can get most chemicals here so will add something to my next batch. Probably to the cold side from what has been said on this thread.
Any suggestions and specific quantities would be appreciated. Not much of a mathematician when it comes to chemistry!
 
Very timely post. Craft Beer and Brewing has a recent episode on fermentation health, with a deep dive on zinc at around the 21 minute mark link. I thought it was fascinating.
I did get around to listening to that episode. It was not mentioned, but I swear I have read that there is plenty of zinc in a new pack of yeast to support fermentation and maybe even for a repitch or two, but that zinc starts to become an issue after a few generations of repitching. Is this not true? Do I need to worry about adding zinc when using a new pack of yeast? Any differences for dry yeast vs liquid yeast? Are there any issues with adding the recommended amount of Wyeast nutrient with a new pack of yeast?

I have been using the Wyeast nutrient for the past several years. I have typically added it either at the last 10 minutes of the boil, or I have added it into my yeast starter. I do tend to transfer quite a bit of trub into my fermenter, so it is hard to say how much of the zinc (and other nutrients?) gets left behind in the kettle. I started to have some concerns that adding the full amount (2.2 g) to a 1L yeast starter was too much in the starter, but looking back it has worked well for me. This would likely mean that the vast majority of the zinc would make it into the fermenter.

If adding directly to the fermenter, is boiling the yeast nutrient in a small amount of water a good idea?
 
If adding directly to the fermenter, is boiling the yeast nutrient in a small amount of water a good idea?
That's what I do. It helps to dissolve the nutrient and make sure it's sanitized. If you have stainless fermenters, you don't even need to cool it prior to adding it if you add it before the wort.
 
I'm considering adding a cup of lentils to my next 5 gal mash. Should give about 4.7mg zinc. Maybe the reason why some brewers added an oyster to their mash.
I don't think it will affect flavour and may provide other (important) trace minerals that are lacking in our modern monoculture farms.
 
That's a good point, so not expecting anything conclusive. At least the soil is from different continents! I figure it can't hurt and will go some way to elevating the zinc. My last brew got fully attenuated and I'll be using the same batch of yeast this time (today, in fact). I'll be using 250g of gelatinized red lentils
Found this interesting:
https://www.mdpi.com/2076-3417/11/21/9817
 
from murphys UK

Zinc is an essential growth factor for many yeasts and it is often low in wort.

Benefits

-Improved yeast growth
-Faster Fermentations
-Reduction of sulphur characteristics
-Concentrated product—economical in use
 
I notice that a lot of dietary zinc supplements are the gluconate. Is there any reason not to use those?

I found one zinc glycinate product. Added benefit - nitrogen. Pricey though.
 
To be honest I was going to use zinc sulphate but brew day arrived and I hadn't been to the shops! I also like the idea of minerals in their natural form. The Ionic Zinc Plus looks like a great product but it's not so easy to have things delivered to Myanmar.
24 hours in the fermenter now and gurgling away like a 2 month old baby. It's Kviek so if the zinc is doing the job I expect it to have finished by this time tomorrow.
 
I notice that a lot of dietary zinc supplements are the gluconate. Is there any reason not to use those?
In a discussion a few years ago, one of our yeast gurus claimed the gluconate makes the Zinc ion inaccessible to the yeast.

IIRC, Zinc Chloride (ZnCl2) or Zinc Sulphate (ZnSO4) apparently are fine to use. But he used one of those dropper bottles with a much more accessible form of Zinc. It was around $20 or so, and swore by it.
 
Okay I'm interested to try this out.
Problem is sourcing zinc sulfate monohydrate food or pharma grade powder from U.S. - not from India as contaminants are my concern.
Suspect 8 oz would probably last me a lifetime.
Liquid versions are my distant second choice.
Anyone have a reliable source?
 
I'm hearing the benefits of cold side addition here in this thread. Anyone try just adding it to their starters when they spin up yeast?
 
Okay I'm interested to try this out.
Problem is sourcing zinc sulfate monohydrate food or pharma grade powder from U.S. - not from India as contaminants are my concern.
Suspect 8 oz would probably last me a lifetime.
Liquid versions are my distant second choice.
Anyone have a reliable source?

This was posted upthread. It's food grade zinc sulfate solution, and US-made.
 
Last edited:
I'm hearing the benefits of cold side addition here in this thread. Anyone try just adding it to their starters when they spin up yeast?
I've not done a proper side-by-side comparison of starter with nutrients and nothing in the wort vs Zn in the wort and nothing in the starter. Whenever I do a starter I put in a pinch of WYeast nutrient (confirmed to have zinc), but I still use it on brew day on the cold side, as I've still found it beneficial there, as well.
 
Just for comparison, price wise, you can buy a whole pound of Zinc Sulphate from Alpha Chemicals for $3.50.

While there, you may add a few other useful things before getting into the next shipping cost bracket. ;)

https://alphachemicals.com/zinc_sulfate
I've shied away from products that are meant to be used in landscaping, for purity reasons. I tried to confirm the purity/grade of the Alpha stuff and their spec sheet is 404. Just FWIW.
 
Back
Top