Why store in a dark cool location?

[Bushman]

This question I tried to research while making Gin. Both Stubby’s and Odin’s gin recipe call for letting it sit for two weeks but doesn’t mention how or where to store after adding ingredients and prior to distilling. Almost every recipe I have read on line and all of the recipes in my Liqueur book during the infusion stage calls for storing in a cool dark location. While researching many times it says that the alcohol level will keep it from creating bacteria, so why a cool dark place.
I am currently infusing the gin prior to redistilling, as it is sitting at 43%. Having made a lot of liqueurs I followed what I have always done and stored it in a cooler room with a towel over it to keep the light off of it. Anyone know why it is recommended as I understand it on cream type liqueur.

[Twisted Brick]

.
According to the Scotch Whisky Association, direct sunlight is the only thing that can degrade a bottle of whiskey. Some drinkers believe that prolonged light exposure can fade the color of brown spirits and result in “off” flavors like plastic or rubber. ... Keep them out of direct and prolonged sunlight.

Another site I read said "it is debatable if light plays a role in the degradation of whiskey", but In short, extended light exposure breaks down organic compounds, which results in evaporation of flavors. To slow that process down, alcohol is sold in glass bottles.

We all know light is detrimental to the quality of beer and wine. Maybe we're just afraid of skunky single malt?

[Bushman]

Twisted that is the best answer I have heard so far.

[kiwi Bruce]

+1 Twisted Brick...chemically/physically what I believe happens is the "O-H" bond on the flavor alkaloids (which are light organic oils) can be attacked by strong light and or heat. When these are dissolved/attached to an alcohol this happens at a much slower rate, so it's during the maceration phase that light and heat can do the most "damage"

[StillerBoy]

Reason: Oxidization

Transferring your dry leaf or herbs to a glass mason jar or blacked out UV-ray jar would extend its life by preventing oxidization. If you do use a clear glass jar, make sure to store it in a cool, dark area. This is because light and heat will degrade the quality of your in product.

Mars

[Bushman]

+1 Twisted Brick...chemically/physically what I believe happens is the "O-H" bond on the flavor alkaloids (which are light organic oils) can be attacked by strong light and or heat. When these are dissolved/attached to an alcohol this happens at a much slower rate, so it's during the maceration phase that light and heat can do the most "damage"

So for not understanding the why but by following what reliable professionals like Andrew Schloss who wrote the book Homemade Liqueurs and Infused spirits I’ve been doing it right. But having a curious mind I just don’t like doing things just because others are without the why!
Thanks gang your the best.

[WithOrWithoutU2]

Just to add a little to what already has been pointed out is the fact light acts as a catalyst for changing chemical compounds in multiple way. One is the heat from the light. But light also has a radiation element to is as well. For example, UV rays from the Sun or Florescent lights can cause reactions to many things. This is how and why even on a cloudy day, you can get sun burned. Different types of light have different types of wave lengths and different types of compounds react differently to these various types of light. All that said, I am unaware of what types of liqueurs (more specifically their ingredients) would react with the different types of light. But there are two sides to that coin. I would have to believe, in some cases the reaction to the different types of light could be a positive given the vast types of ingredients that can be infused into liqueurs. But I think the prevailing guideline for "cool and dark" is more precautionary as a "better to be safe than sorry" principle.

[Twisted Brick]

.
Different types of light have different types of wave lengths and different types of compounds react differently to these various types of light. All that said, I am unaware of what types of liqueurs (more specifically their ingredients) would react with the different types of light. But there are two sides to that coin. I would have to believe, in some cases the reaction to the different types of light could be a positive given the vast types of ingredients that can be infused into liqueurs.

Good point. Apparently, certain wavelengths of light can have a positive effect on spirits, in this case rum.

http://www.spiritedbiz.com/bryan-davis- ... g-spirits/

[Demy]

As has often been said (especially for liqueurs) there can be an interaction between UV rays and organic compounds, this can also happen for example with hops / must. However, I believe it is often "preventive" advice, to stay safe. I've actually seen old liqueur recipes where the mixture is supposed to be put in the sun. I believe it all depends on the ingredients.

[jonnys_spirit]

I've got some orange buckets in my porch garden for the past few months that have faded considerably from bright orange to a sickly yellowish color. I can imagine that the sun would similarly fade something out of the spirits that we would want to preserve.

Cheers,
jonny

[freebase]

as we are coming to understand, in general UV is 'damaging' to most things.
It will give you a nice tan or burn you.
It will also allow any photosynthetic bacteria/microbes to earn a living.

It will provide energy to damage chemical bonds, and effectively bleach some liquids in direct sunlight.
UV is a certain wavelength of light.
It comes in from the sun.
Certain compounds respond to this light energy, and effectively 'warm up'.
Generally, this causes a reaction that creates heat, and the absorbing body generates infra-red radiation.
Giving out heat, being generated, where it would have been absent in darkness.

Generally, compounds that are sensitive to light should be kept in the dark.
Light/heat is not required for their fermentation reactions.
Also, these reactions can (at certain threshold temperatures) become exo-thermic, and generate their own heat.
Any externally provided heat (sunlight) can crowbar a standard reaction into an abnormal condition.

Also, dark conditions, are generally cooler...

Rgds.

[jonnys_spirit]

Plus it just feels better pulling the cork and tipping the jug up in the dank dark cellars far from the light of day and prying eyes. For testing of course. Ahem...

Cheers!
-jonny

[n_plains_drifter]

Twisted,

We'll all agree that we don't want skunky single malt or pretty much anything else that we've worked so hard on.

The good news is that the reason beer gets skunky when exposed to sunlight (or even some fluorescent sources) is a the light reaction with some of the compounds in hops that flavor and bitter beer.

Hopefully that will lessen the potential that a stray photon or two will skunk out a nice bottle a'.

[contrahead]

Why store in a dark cool location?

To my shame I have had several occasions to regret my inattention and lack of studiousness back in my chemistry classes of yesteryear. Any brain cells which I still retain to date, have undergone six decades of assault from crude alcohols, chemical plant alkaloids and perpetual cosmic ray bombardment.

I have no sagely “expert” advice to add on this subject but I do have a few controversial observations. First, let me agree with “TB's” link or input about the probable detriment to Scotch whisky under direct and prolonged sunlight. Prolonged exposure to broad spectrum electromagnetic radiation will probably cause damage to all organic compounds and to many inorganic compounds as well. But consider, that without sunlight there would be no organic life to begin with.

Without photosynthesis (sunlight powering chlorophyll to produce carbohydrates) there would be no whisky nor Scotsmen to drink it. By the way chlorophyll does not absorb that spectrum of visible light we call “green”, but instead reflects green light. White sunlight bounces off a leaf or a blade of grass and into our face and we see green. But it is the blue and red wavelengths to either side of green in the wider spectrum, that are being absorbed to preform the all important work of photosynthesis. When winter comes and plants change colors; that's because the chlorophyll departs and the other pigments also in the plant structure begin to show. Plant pigments like carotenoids (yellows. orange, reds), xanthophylls (reds) and anthocyanins (blues, purples and reds) that absorb differing portions of the light spectrum and also no doubt, produce differing important organic compounds.

-----------------------------

I still have two old bottles of my flavored brandy, remaining in the cubbard. The oldest bottle I capped in 1981, and its whole cherries are still floating around in a dark, rich red liqueur. The bottle has been stored in the dark. Had it been exposed to continuous direct sunlight these many years it would not be red and I don't even care to speculate on what it might have tasted like. But here is the rub or the controversial part. I believe it is possible come close to replicating the quality of such brandy in just a couple years, using sunlight...

There are threads in this forum dedicated to ways of accelerating the maturation of new spirit. Nuking white dog along with barbecuing chips made from used Bourbon kegs does work, to a point. The process is expensive and not efficient. The nuked-oaked product is drastically changed but not necessarily that good. I and others have speculated on how ultrasonics can be used to accelerate the maturation process. But microwave and ultrasonic radiation take equipment and electrical power. The sun already produces visible and invisible light, gamma rays, x-rays, radio waves, microwaves and sound waves. The earth's atmosphere blocks out about half of the sun's radiation before it reaches the surface but that still leaves enough left over to do useful work (aside from already driving all life on the planet).

“WithOrWithoutU2 commented that - light acts as a catalyst for changing chemical compounds in multiple way”. That's right. Ever hear of “sun tea”? You just drop some dry tea, sugar and mint into a glass jug full of water and wait a few hours as the sun works on it. You'll end up with a better tasting tea than you could have made by boiling the hell out of it.

To cut to the chase, my general modus operandi for maturing spirits these days is to put my product into big glass bottles and to set these bottles in a windowsill for full daytime exposure to sunlight. Naturally I'll include some dry solids in the bottle for the solvent to work on. Homemade charcoal or oaking sticks by themselves are certainly adequate. But I've found other dry agents rich in phenols (like some freeze dried fruits) will produce admirable results too. The longest period that I've managed to allow my suntea (“sun-shine” don't work) to set in the sun has been 6 months. The ammount of change or maturation was sensational (but the product got consumed a little too fast). So far I've decided that 2 months exposure to sunlight is too little. At that point perhaps not even all the floatsum in the bottle will have settled. I've not decided on a maximum exposure yet but would predict that one year might be adequate. At which point the liquor would be filtered, re-bottled and set back in the dark to be forgotten about.

[8Ball]

The comments on ‘uv light’ et al might also explain why Laphroaig bottles are green ....