Sunday, September 2, 2012

What on earth are enzymes?

Certain aspects of winemaking - yeasts, oak-ageing, filtration and fining are pretty clear but what about the use of enzymes? Even the comprehensive Authentic Wine by Jamie Goode and Sam Harrop only contains one paragraph on the subject.

I can’t remember how but I got into a discussion about it on Twitter a couple of weeks back and asked if anyone would volunteer to write a post on them.

Two young winemakers Leah de Felice Renton and Nick Jones who are part of a wine collective called Birds & Bats Wine Productions which makes ‘a series of one-off wines from around the globe’* bravely volunteered. Not being a scientist I have to say I couldn’t make head or tail of their first version so they kindly offered to rewrite it for dumbos like me. Here's their guest post:

"Enzymes exist naturally in wine and are also added to wine.  This subject is of interest because it is something most people don’t know about and it goes into a product we all regularly and happily pour into our bodies.  We are joining the fish fight, we are drinking real ale, and we are reading this natural wine blog because we are more curious than ever about what we are eating and drinking.  We are writing this so you know what we are putting into your wine and into your bodies and why.

Enzymes are like your front door key. There is one key for a particular door, or in the case of enzymes, one chemical reaction it can trigger. That reaction can happen in other ways but using an enzyme speeds it up.

Enzymes can be found everywhere.  They are in your mouth, in the trees, in your washing powder, in your tears, and even in that piece of cheese.  They affect the way you taste that glass of wine and they help you through a hangover in the morning.  Without enzymes we would have almost nothing and more importantly wine would not exist. 

Wine is the consequence of thousands of different enzymes doing their thing to grape juice. These enzyme keys are found naturally in the grape, in yeast and in the bacteria we use in winemaking.  Therefore, in order for us as winemakers to turn grape juice into a specific wine style, we must try to predict and control thousands of these enzymes.  As with much of the natural world we don’t understand it all, but in the last half a century or so, we have been able to establish a good grasp of the subject.

In this post we will spare you the complex, confusing and sometimes yawn-inducing enzymatic pathways of yeast and bacteria.  Instead we will give you an insight into commercial enzyme formulations that winemakers add to the wine you drink.

Commercial enzyme preparations have been added to wine since the 1970’s and have been subject to technological advances since that time.  They are produced from a range of natural, non-G.M.O. fungi using methods that are controlled in Europe by the International Organisation of Vine & Wine. Enzyme formulations aid winemakers by releasing and maintaining red wine colour; releasing and increasing aroma precursors (that the yeast use to give a greater assortment of aromas); improving the clarity and improving mouth feel and roundness of wine. 

There are many practical advantages to be found in the addition of enzymes during the processing of grape juice into wine that makes life easier for the producer and reduces cost to the consumer.  We add enzyme formulations to juice and wine because it allows us to speed up the winemaking process, protect consumers’ health (by avoiding infection of unwanted micro-organisms), release more potential from the grape and ensure the wine does not spoil.  It is in our interest as winemakers to protect our customers and to deliver a quality wine.

Essentially we will be using enzyme additions this year in the production of our own wine.  We cannot afford to spoil thousands of good grapes and we want the best for the person that cracks open the bottle.  This way we can reduce the cost to the consumer and make less of the sinister chemical additions such as the dreaded sulphites.

There is always a down side and it generally occurs in wine when a producer doesn’t understand what they are doing.  If you season a pan with pepper before you add the steak you scorch the pepper.  The result is substandard steak.  If you add the enzyme formulation at the wrong time you are likely to end up with substandard wine.  As with the execution of any quality product, prior preparation and planning prevents piss-poor performance!"

Now I’m not sure how many of the readers of this blog will agree with this. ‘Natural’ winemakers, I imagine, don’t add** (see comments) enzymes which according to Goode and Harrop are also used to boost yields so do pitch in with your views.  I'm happy to give a platform to anyone who wants to state the case against!

* Incidentally Leah and Nick pledge on their website to include 'every last detail of what is contained in the bottle'. I wish more winemakers would do the same. This year they’re working in Maury - you can follow their progress on their blog and on Twitter @WinesofMD (Wines of Momentary Destination - which is what they call their winemaking projects).


  1. Interesting introduction to enzymes. Obviously from a natural wine perspective it's about minimal intervention, express the terroir and all that.
    What alarms me about the context of the article is that grapes are being sourced from, one hopes, a caring conscientious grower who is apparently happy to sell grapes (or grape juice?). This will then be manipulated by skilled winemakers to create, presumably, a desired style (their blog doesn't say what this style is).
    Much better to control the whole grape to bottle process in my view, but I don't doubt these guys will do better than many of the local Roussillon growers.

    1. Eagle eyed as ever thanks for that one Tony.

  2. Hi Fiona

    To be correct your statement "‘Natural’ winemakers, I imagine, don’t use enzymes" is more correctly written as "don't add enzymes".
    They certainly use enzymes, and have to rely on the indigenous enzymes in the grapes, yeast, bacteria to do the desired work. Without enzymes nothing happens in biology.

    Tony Milanowski

  3. Tony, you're absolutely right. Slip of the keyboard ;-)

  4. Enzymes are biological molecules that catalyze chemical reactions.A living system controls its activity through enzymes. An enzyme is a protein molecule that is a biological catalyst with three characteristics. First, the basic function of an enzyme is to increase the rate of a reaction. Most cellular reactions occur about a million times faster than they would in the absence of an enzyme. Second, most enzymes act specifically with only one reactant to produce products. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates sufficient for life. Since enzymes are selective for their substrates and speed up only a few reactions from among many possibilities, the set of enzymes made in a cell determines which metabolic pathways occur in that cell.@

  5. One more comment is needed, I think: one must be more specific about “enzymes”. There are so many different types, as already explained, and commercially available preparations vary considerably, from “one single type” to a “complete mixture”. The more complicated the preparation, the more likely you are not to master anything. It is essential to understand this:
    some enzymes attack the cell wall of the grape berries by destroying pectines, thereby liberating colour and facilitating the “liquefaction” as well as later clarification of the most. Some others attack the cellulose of the cell wall (what our guts enzymes cannot do, for instance: look at the result when you eat a cassoulet !). Some others still will destroy glucanes (a by-product of Botrytis = rot, be it black or noble), which are present in the yeast as well. Finally, another type (the glycosidases) acts on the aroma precursors and can lead to a whole range of aromatic deviations, changes, modifications. To top the bill, lysozyme preparations are also available, which influence to a large extent the process of malo-lactic fermentation.
    So you see, Fiona, there are at least two main types: one – which I’ve been using myself in some cases – that will increase the speed of destruction of the cell wall and facilitate many early processes. You can do without but they make your life easier and won’t alter – in my experience – the final “taste”. I speak mainly of galacturonidase. And many others which will definitely influence the “natural” final bouquet of your wine. I have no “hands-on” experience with those and, honestly, I cannot be bothered. But maybe I’ll change my mind some day, even though I have the feeling the confidence you gain from the accumulation of experience with the passing of time (8th harvest this year !) incites you to use less and less “additives”, whatever they be !

  6. Pectinase enzymes used in winemaking also occur naturally in grapes but the grape pectinases are not very active under winemaking conditions. That is why winemakers add commercially produced fungal pectinases to assist their winemaking processes. Pectinases help with juice settling and thus clarity. The clearer the juice before fermentation (within limits)the finer the aromatic finesse of a white wine. Doing skin contact with enzymes on white grapes before fermentation also increases juice yields and extraction of aromatic precurcers. The use of enzymes in red winemaking improves wine colour, colour stability as well as clarity and filterability of wines. Using glucanase enzymes for ageing on yeast lees, one increases the complexity and mouthfeel of wines. All in all the use of enzymes in winemaking has a very positive outcome on wine quality.

  7. Hi Fiona,

    I came across your article in the Guardian which I really enjoyed. I think your traffic light system is an excellent way to introduce people to wine (not just natural wine).

    I write a blog for Excelsior Wine Estate - The Horse's Mouth. We have just posted an article on Natural Wine with a link to this blog and your Guardian article. I thought it might be of interest to you.

    Kind regards, Emily

  8. Love the post here by Leah de Felice Renton and Nick Jones on the use of enzymes in wine. Great write-up for the lay person!

  9. While some experts recommend using solutions of dissolved sulfur to store barrels, liquids will drain the oak flavor from your barrels and shorten the useful life of your barrels.

  10. Quite interesting article regrading natural wine. I just come across to article and I found it much helpful about how these natural wine production is done. Thanks for discussing with us. Keep giving such interesting article to us.

  11. I believe a considerable amount of confusion would be removed from the who issue of "natural" wines if we were to star referring to them as "minimalist". There's just far too much in-fighting over semantics in what actually constitutes "natural". Instead, let us strive to reduce the complexities of this battle - much like the wine - to what it really is, a minimalist approach in how the wine is produced.

    Would it really be that difficult to establish a system in which wines are rated on a tier system (e.g. M1, M2, M3, etc.) that would be considered a standard for all "natural" winemakers to follow? M1 - as an example - would be a wine unaffected by any process beyond what nature would allow. That is to say it's an organic/biodynamic/biotrope vineyard and the wine is produced with little to no intervention - oxygenation, designer yeasts, etc. This would be wine in its most "natural" state possible. M2 would be some intervention, M3 more, and so on. And most importantly - anything under this structure would have to list any additives as it progresses on through the various tiers.

    Perhaps it's all too much anyway. As anyone who has a passion for wine and a real interest in "natural" wines they're going to be looking to people like Alice, Jim, et al. to give them low-down on what's what these days anyway. Anyway, that's just my thoughts on the matter.


  12. Thanks for all the comments.

    @ Miss Bacchus I am glad you found the blog easy to digest.

    @ Luc @ Anon @ Zsivra All textbook responses but the idea of the post was to be approachable and not yawn inducing raw science. I am sure Ribereau-Gayon would be proud of what you have written but public understanding is what we were after here.

    Many thanks,



  13. Some great points mentioned here. It's a very good practice that Leah and Nick includes every last detail of the ingredients used on their wine. I'll be subscribing to their blog.

  14. Thanks for the precise and more education explanation.