Water Chemistry - Additions Of Zinc

[manticle]

I'm currently at the tail end of writing a summary on water chemistry for some colleagues in a bjcp study group. When it's finished and checked by a few other knowledgeable blokes, I may post it in the articles section (with better referencing than required for its current intended purpose).

However one thing that's come up in my reading is that zinc ions and their levels seems to be neglected in most homebrew references to water chem (yet adding carbonates/bicarbonates to water is seen as worth recommending).

Just reading Bamforth and Lewis who suggest that malt contains zinc but not enough and wort may be/usually is zinc deficient. I know commercial brewing yeast nutrients contain zinc but to me that's a bit like adding 5.2 buffer. Is there anywhere you can work out what your existing zinc levels are and any recommended method of supplementing those levels? I'm talking about methods your average homebrewer can apply so HPLC is obviously out.

I can buy calcium chloride, calcium sulphate and other salts that I have no wish to use. What about zinc?

Cheers for any relevant info or ideas (or alternative viewpoints to Bamforth and Lewis).

 

[Bribie G]

The brown yeast nutrient as sold by the likes of Craftbrewer contain Zinc, deliberately of course, as this is not common in Aussie malts or water. Also traces of all the stuff you need such as unobtanium, etc.

Yeast book stresses Zinc as well.

 

[MHB]

Following are a couple of pages from The Yeast in the Brewery VLB Manuals by Annemller, Manger and Lietz English edition 2011
This is the newest publication form the people that bring us Kunze and should represent the most recent thinking in yeast research and management.
I will remind brewers that Australian malt is often the lowest in Zinc (the joys of living on a very old continent). I would suggest that for the miniscule amount it costs a teaspoon of nutrient in the mash is a pretty small amount to pay to insure that your enzymes are getting ALL the trace elements they need not just Zinc.
I sell food grade Zinc Chloride but if you look at the requirements you would be a long time between purchases and its not something you want to over dose on, too much can be quite toxic to yeast.
Defiantly something to consider and well worth discussion, personally I use a pinch whenever I use Australian malts.
Mark
View attachment 53669View attachment 53670

 

[manticle]

@Bribie:

Yeah I use the wyeast nutrient but how does it calculate how much I need? How do I calculate how much I need? How do I recommend to others how much I need? How much does the nutrient contain and what else. Like I said - is it a bit like adding 5.2 buffer and hoping for the best?

EZ water calculator, for example is great at calculating chloride, sulphate, calcium and carbonate levels. From my reading, zinc seems important and forgotten in water chem simplification documents and not everyone has access to more complex tomes like Briggs et al (I found one on Amazon today for well over $1000).

According to Bamforth and Lewis, Zinc plays a major role in foam stability, works as a yeast nutrient and facilitates certain enzymatic reactions and has a role in reduction of acetaldhyde.

They do suggest .02 ppm but I don't know if that's an addition or a minimum total. Since too much of any ion is bad for yeast and finished beer, it would be good to work out how much and when, like we have with various other ions.

Not interesting to the teaspoon of gypsum crowd or those who don't find 'anal'-ysing over this to be of interest but of interest to me and possibly some others.

@MHB:

Cheers. Will have a read and digest.

 

[MHB]

If you went to a chandler and brought the smallest Zinc anode they sell and throw it in your HLT you will get all the zinc you need no Im not being flippant!
Really it is a trace element, if your house has galvanised pipes you will be getting enough, modern copper or plastic plumbing you probably arent.
I think is something to be aware of but not something to get wound up over. The amount required to do harm is reasonably high and the requirement so low that any measure taken to ensure some is available will be adequate.
Following might help you
Mark
View attachment WYEAST_NUTRIENT.doc

 

[manticle]

Cool, thanks for that.

I have zinc washers in my HLT.

Just trying to get my head around the science of it (on a basic level at least)

Appreciated.

 

[eamonnfoley]

Gordon Strong - probably the best guy to listen to given your studying for the BJCP and he is the BJCP chief - says (in his book) that zinc is the only mineral needed for fermentation that is deficient in barley. Therefore nutrient with zinc is a good insurance policy.

I use Wyeast nutrient also - dosage is 1/2 tsp for 20L. I dont think you need to be more accurate than that.

Also read in one of the brewing science books that zinc making into the fermenter from malt is very hard to quantify because some is lost during the mashing / sparging process in spent grain etc.

 

[manticle]

The amount required to do harm is reasonably high and the requirement so low that any measure taken to ensure some is available will be adequate.

Probably the most important point to take from this so far.

I am still interested in exploring further and answering my questions more precisely but for the purposes of writing a simplified discussion article about water, mash pH and ions in brewing, this makes complete sense.

Just didn't want to direct other people to the popular idea that there are only certain set of ions of importance and that anything else is insignificant or taken care of in an all malt, all grain wort if that was not quite true.

Important but easily attained and not easily exceeded unless you try, summarises what I get from the above.

@Foles: Cheers.

 

[bigfridge]

If you went to a chandler and brought the smallest Zinc anode they sell and throw it in your HLT you will get all the zinc you need no Im not being flippant!
Really it is a trace element, if your house has galvanised pipes you will be getting enough, modern copper or plastic plumbing you probably arent.

Of course adding such things were strictly prohibited by the German Purity Law, but I have heard/read stories of German brewers who have 'accidently' forgotten about leaving a galvanised steel ladder in the brewing kettle after routine maintenance.

Seemed that they didn't have any problems with zinc deficiency.

 

[RobW]

I always add zinc sulphate to the kettle 10 minutes before the end of the boil.
Can't find the calcs atm but cn dig them out - originally from the oz.Craftbrewer which appears to be no more.

Also an interesting read attached.
View attachment Fermentation_28___Effect_of_zinc_and_other_metals_on_yeast_growth_and_fermentation.doc

 

[drsmurto]

I use rainwater and the roof is galv.

A few years ago i measured the metal ion content (as well as S, Cl and a few other brewing relevant ions) using ICP-MS and ICP-AES (detection levels of ~0.1 ppm) and found Zn levels i wasnt expecting. I don't have the data on hand but from memory it was a few ppm. I did this to get a better understanding of the water i use for brewing and as it turns out, other than a little bit of Na my water is effectively 0 ppm in all the brewing salts.

I also add yeast nutrient (from Craftbrewer) at the rate of 5g (teaspoons are volume not mass measurements) per 20L batch and find i get better attenuation, reduced lag times, faster fermentation and a reduction in yeast related faults (acetaldehyde, diacetyl, acetic acid, ethyl acetate etc).

I have read academic papers on this topic and the observations reinforce what has already been stated in this thread "during the production of wine and beer, the yeast Saccharomyces cerevisiae can encounter an environment that is deficient in zinc, resulting in a 'sluggish' or a 'stuck' ferment."

Interested to read Zn also has an impact on the mash enzymes, will do some more reading on this but i suspect my rainwater is providing enough Zn for them. That and using a Fowlers preserving urn with an exposed element that is older than me (dial is in fahrenheit) as my HLT - doesn't look like stainless steel to me.

@Manticle - if you would like someone to read over your article I am happy to help out. Genuine offer, chemistry is what i do for a living.

 

[manticle]

I use rainwater and the roof is galv.


Interested to read Zn also has an impact on the mash enzymes,

My understanding was enzymatic acticity in relation to yeast rather than mash

@Manticle - if you would like someone to read over your article I am happy to help out. Genuine offer, chemistry is what i do for a living.

Absolutely. Much appreciated.

Should I email it to you (word docx)?

@RobW: that article is great, thanks.

 

[hefevice]

Another thing to consider is when the zinc is added to the boil. A fair amount of zinc can be lost in the hot break, which is why it is recommended that yeast nutrients are added towards the end of the boil.

This section from "Yeast, The Practical Guide to Beer Fermentation" (White and Zainasheff, pp75) might be a useful reference for your article:

"...The ideal range for fermentation is 0.1 to 0.15 milligrams per liter. You can use either food grade (FCC) or pharmaceutical grade (UPS) zinc sulphate or zinc chloride. One thing to be aware of when determining dosage and cost is that FCC or USP grade of zinc sulphate is invariably zinc heptahydrate salt (ZnSO4.7H2O), which is only 23% zinc by weight. On the other hand, zinc chloride is 48% zinc by weight. Also keep in mind that some of the zinc is absorbed by the hot break, and you will need to add more than the target amount for fermentation. Adding approximately 0.2 to 0.3 mg/L of zinc near the end of the boil should result in a high enough zinc level in the fermenter."

In terms of availability of zinc to the yeast, a following section on the same page reveals (consistent with the extract from the VLB Manuals posted by MHB):

"Even when wort has a technically sufficient mineral composition, it does not guarantee the minerals are bio-available to yeast cells. Metal ions tend to chelate, meaning that they bind to proteins or other compounds, making them unavailable to yeast. Even when metals successfully enter yeast cells, they can chelate within the cytoplasm. This is actually a natural defense mechanism for yeast, and it helps keep toxi metals from hurting fermentations."

It then goes on to plug the yeast nutrient products of one of the authors, claiming that chelation is avoided due to the way the nutrient is produced (it is basically yeast grown in the presence of high concentrations of the target metal ions, such that the ions bond to the cell walls). It would be a fair bet that the Wyeast nutrient works in a similar manner.

 

[manticle]

Good info. Was reading today about the amounts of zinc present in the mash being unavailable to the yeast due to chelating. Mash pH is one way to help reduce that (and increase available zinc) so that ties in well.

Actually read that in the link provided by RobW.

I've got the yeast book next to me to check references for that.

Simplifying things accurately is complicated.

 

[Florian]

Got this recently for non brewing related purposes.
Is this the stuff we're talking about? Would be good to have another use for it as 250g is more than I could use in three lifetimes.

 

[hefevice]

Got this recently for non brewing related purposes.
Is this the stuff we're talking about? Would be good to have another use for it as 250g is more than I could use in three lifetimes.

Yep, that will do the job, but it is slightly different to the stuff mentioned in the reference I posted. By my calculations, the stuff you have is ~36.5% zinc (monohydrate rather than heptahydrate). To get 0.3mg/L in a 20l batch you would need 16.4mg. Might be a bit hard to measure. Perhaps dilute 1.6g in 1 L of water and use 10ml per 20L batch (assuming that the stuff is soluble).

Using it for brewing might bring it down to 2.75 lifetimes

 

[the_new_darren]

How much zinc in the water used to malt the barley?

Probably enough for a trace nutrient required by yeast.

tnd

 

[hefevice]

How much zinc in the water used to malt the barley?

Probably enough for a trace nutrient required by yeast.

tnd

If you read back through the thread, you will find that the answer is "not enough", and further what zinc is in the malt tends to get bound to proteins in the hot break during the boil. This is supported by several references, and according to MHB, Australian malts tend to have very low levels of zinc.

 

[MHB]

Zinc Sulphate will certainly work, I chose Zinc Chloride but both are highly soluble hefevices idea of making a stock solution is a good one.
Australia is an incredibly old place lots of soluble stuff got washed out to sea millions of years ago; its just something to be aware of. Aussie malt does tend to be lower in Zn than other malts.
Zinc is very useful in the mash and the boil as well as the ferment I tend to add it into the strike water was it can help the mash enzymes and hopefully enough will carry over to do the other jobs.
Just dont get carried away with it, overdosing is not a good idea.
Mark

 

[RobW]

This is lifted off the Oz.Craftbrewer site Yummies for Yeast article by Graeme Sanders in Materials & Methods

Zinc Solutions

Two common sources of zinc are Zinc Chloride (ZnCl2) and Zinc Sulphate that normally has water attached to it (ZnSO4.7H20). This hydrated ZnSO4 is still a crystal, it just absorbs water from the atmosphere. You can get these from school labs or lab suppliers.

In these examples we are looking at adding 0.4ppm of zinc to the final wort.

ZnCl2
Make a solution of 4.17g ZnCl2 (dry) per litre of de-ionised or distilled water.
This solution contains 2mg of Zinc per mL.
So for 20L wort you add 4ml to get 0.4 ppm Zn in the wort

ZnSO4.7H20
Make a solution of 35 grams of ZnSO4 per litre of deionised or distilled water.
This solution contains 8 mg of zinc per mL.
So for 20L wort you add 1ml to get 0.4 ppm Zn in the wort