Wine salvage

[tonyhibbett]

I've had a lot of problems this year with acetification of wine in casks. I think the problem is to do with the long hot summer. I don't have the luxury of a cellar, where conditions are generally cool, damp and stable. Under such conditions, water slowly evaporates through the pores of the wood and air is sucked in by the vacuum created. As a result, the wine becomes more concentrated and the slow oxidation makes it taste smoother. However, in sustained hot and dry conditions the rate of evaporation is significantly increased and the level of liquid needs to be topped up to prevent the top of the cask from drying out, which allows bacteria to enter through the wood joints. The worst offender is acetobacter which, given warm conditions and an oxygen supply, turns alcohol into acetic acid and acetone, i.e. vinegar. Left undetected and unchecked, you get sour, undrinkable wine with an unpleasant smell. Typically vinegar contains 5% acetic acid, which is 10 times the amount normally present in wine. Although my wine had not got to that stage, it was far too acidic and smelled 'off'. One cask contained 10 gallons of 1 year old pinot noir and I was not about to tip it down the drain!
I kept adding potassium bicarbonate, which caused it to foam violently. In all it took about 400 g plus 200 g of calcium carbonate to get rid of the smell and reduce the acidity to an acceptable, drinkable level. The dosage was far in excess of that recommended and supposedly this creates an off-taste of it's own, caused by the by-product salts created. Fortunately this did not happen.
Normally, the main acids in wine are tartaric and, to a lesser extent, malic. I couldn't find any information about the effect of potassium bicarbonate on acetic acid but it is well established that it starts to work on tartaric acid initially, whereas calcium carbonate works on both tartaric and malic acid at the same time, thus preserving the balance of the two. I have no way of measuring the levels of the individual acids now present other than by taste. All I can say is that it is now smoother and more pleasant to drink but lacks the really good flavour an aroma it once had and is somewhat deficient in tannin, which is also an acid. So I added 5 level teaspoons, dissolved in enough sulphited warm water to top up the cask.
Using a vinometer, I measured the abv as 12%. Considering that the acetobacter must have used up some of the alcohol, this suggests that only water evaporated from the cask, thus concentrating the alcohol (and the acidity).
Anyway, lessons learned. As I can't control the temperature and humidity, I should keep a supply of topping up wine and regularly maintain the level during hot dry weather. Of course, each time you remove the bung you run the risk of exposing the wine to infection so a little sulphite added to the topping up wine for protection is a good idea.
Cask size is an important factor. The smaller the cask, the greater the rate of evaporation. I have a 14 gallon cask which was subjected to the same weather (stored outside). The wine was also 1 year old and did not suffer the same fate. I have smaller (5 gallon) casks which were affected but to a lesser extent, possibly because they are stored indoors where the temperatures 915-20) and humidity (no central heating) are less extreme, due to an air conditioning unit.

 

[Dutto]

Impossible to hit the "Like" button and there isn't one for "I feel your pain!"

The "size v. evaporation" is spot on. It's why wales are so big but in their case they are reducing heat-loss.

Have you considered wrapping the barrels in insulation or building an insulated enclosure for them? Even partially burying the barrels (something like a WW2 air-raid shelter) would give the wine a much more stable environment; especially if you only went in there during the night!

Global warming is a fact of life and we are all going to have to find a way round it! Here's what may be a useful site for you to look at ...

https://www.andersonshelters.org.uk

 

[tonyhibbett]

Actually there is a brick built communal air raid shelter under a shed at the back of the garden 3 doors along with right of way access! More practical and accessible is my small lean-to north-facing shed which is 2 feet below the garden and, being overshadowed by vegetation, never gets direct sun and is usually damp. I store a lot of bottles of wine in there and has a worktop which would accommodate several casks if it were not already full of other stuff!
A useful ploy with small casks is to varnish the stave ends, through which most of the evaporation occurs. I have done this with 3 small casks, 5, 7 and 9 litres and this works well to reduce fluid loss and I may do the same with the larger ones. In fact my latest cask (22 litres) came with painted ends.
I have also decided to maintain a supply of top up wine beside each cask. To this end, I have brewed a 5 gallon kit of Australian blend premium (cheaper!) cabernet sauvignon and topped up all of the red wine casks. This used up half of it! The rest I have put in demijohns to be held in reserve for future top up sessions.

 

[tonyhibbett]

In order to further reduce evaporation I have rotated the casks 45 degrees to prevent the bungs (both wooden and cork) from drying out. After some initial seepage, which proved the bungs were neither water nor gas tight, the red wine evaporated, leaving a sticky residue which seals the joint. White wine does not do this, so I applied Vaseline to achieve the same effect. One wooden bung still leaked due to an imperfect fit. I found an old expanded champagne cork which, with a little trimming and sanding, made a good tight fit and also provides both a handle and a flange. I also varnished one end of each of the 5 gallon casks.
It seems that full size (136 gallon) wine barrels only lose about 4% over 2 years and that alcohol only starts to evaporate when the humidity reaches 60%.

 

[tonyhibbett]

White wine continued to seep from the 2 smallest casks so the strategy proved counter productive. Anyway, the wine is much improved after just 21 days and ready for bottling. I currently have nothing with which to refill them so I''l just use sulphited water. My tub of sodium metabisulphite powder has a bb date of 17/12/12 and no smell at all. I have read that it's shelf life is 3 years so I have ordered more. However the campden tablets, although even older, still smell potent.

 

[Dutto]

....... I currently have nothing with which to refill them so I''l just use sulphited water. .......

I have the reverse problem!

My Mum (*) bought me a small whisky barrel that holds about 2 litres of whisky. (It has a remarkable rate of evaporation and has been know to empty itself in just one session with a neighbour!)

The cheapest of all whisky will improve if left in there for a few weeks but every so often I have to refill it with wine and let it sit for a few weeks to maintain the "improving qualities" of the barrel.

Luckily, this is not too onerous a task for us as A) I get cheap wine whenever I go over to France and B) We go over to France for up to three months at a time and this gives the barrel plenty of time to get the wine flavour back into it. A "Win-Win" situation if ever there was one!

(*)

I can't have a drink out of the barrel without remembering who bought it! That was a lady who knew exactly the kind of Christmas Present that her son would appreciate and use in the years ahead; if he lived long enough!

 

[tonyhibbett]

I once paid rather too much for what looked like an oak barrel, complete with wooden stand, tap and cork bung, at a boot fair. It turned out to be a convincing fake, made of plastic with a plastic liner and only held about 3 litres!
It seems made 2 other mistakes with my pinot noir. Because it is a low tannin variety, it should only be matured in oak for 1 year, not 2. Furthermore, the cask was old and made no contribution to the tannin. I just tested the sulphur dioxide content which turned out to be 25 ppm, (where 40 ppm is recommended for red wine) even after I had belatedly added some sodium metabisulphite, (which turned out to be well beyond its expiry date) so I guess the sulphur dioxide content had been zero, which is unsurprising after 2 years. Both tannin and so2 have preservative qualities and it was deficient in both. I have now added fresh tannin and sulphite.
I once made a test kit for sulphur dioxide, using the Ripper titration method, which is unreliable for testing red wine. I now have the Harris sulphite test strips, which were hard to find but well worth it. They work out at 35p each and can only be used once.

 

[Dutto]

I............. I now have the Harris sulphite test strips, which were hard to find but well worth it. They work out at 35p each and can only be used once.

That is expensive!!!

I'm glad to say that I can buy a litre of quality "en vrac" red Merlot for about €2 over in France so I take out 2 x 10 litre PB's of beer and bring back 2 x 10 litres of Merlot whenever we go over there! (Plus a few 3 and 5 litre boxes of "drinking wine" and a couple of cases of "sipping wine" for when we have guests.)

Here's hoping that they don't start introducing any restrictions of amount or adding Customs Duty to wine bought in France after 29th March 2019!

 

[goodolpete]

"Although my wine had not got to that stage, it was far too acidic and smelled 'off'."
Tony, did you measure what pH the wine had off the yeast and at that stage?

 

[tonyhibbett]

No, but I did a titration test which suggested the acidity was 3 times higher than normal!
I have now done what I should have done a year ago - rack the wine into airtight containers. In order to 'normalise' it, I siphoned the first (ie bottom) quarter into one, the next half into another and the rest into the first container, yielding a total of 44 litres. I then compared the results with the refractometer and got the same readings. The pH is now 4.9 and the TA 7.5 ppt (t), not too far off the mark and perfectly drinkable. It should improve in the airtight containers. I have enough empty (est. 53 required) bottles but as yet not enough rack space to store them.
I have cleaned and sterilised the cask and filled it with water for the time being.

 

[goodolpete]

"The pH is now 4.9 ".
Interesting. I thought (incorrectly obviously) that wine pH sould be 3.5.

 

[tonyhibbett]

No, you are right. The range is typically 3-4. However, when you start trying to radically reduce acidity by adding alkalines, such as potassium bicarbonate, strange things happen to the pH. This is why I rely on titration to asses Total Acidity, expressed as parts per thousand tartaric acid, this being the principal acid in grape juice. This is typically in the range of 5-7. The best test is taste. Flat and insipid = too little acid. Sharp on the back of the throat = too much! However, given the same level of acidity, a medium wine will taste less acidic than a dry one.

 

[tonyhibbett]

To complete the task, bottling is required. Half (5 gallons) of the wine is in a Wilco fermenter with tap. First step is to gather together and prepare 30 similar screw top bottles without labels or collars. Then load up the label template for pinot noir, change the date to 2016 and print them out - 8 per sheet, so 4 sheets = 32. I used a bottling wand, which fits over the tap, for the first time and boy does it make the task easier. The main shortcoming is that it is designed for bottles to be used with corks and automatically leaves enough air space in the neck but a bit too much for screw caps. The other limitation is more to do with the height of the tap, which meant I had to fill the last 4 bottles by the usual method. It's not entirely drip free, so I used a bowl beneath, which collected a mere 100 ml of waste. To save my back, I used a stool to sit on. It takes 20 seconds to fill a bottle but does so without splashing, foaming or aeration.
I can't remember the last time I did 30 bottles of wine in one session before, because I use polypins instead. I stacked them bin fashion in the carcass of an old chest of drawers, using the cut shortened draw fronts as a shelf, as I don't have enough wine rack space.
I could leave the remaining 5 gallons in the pressure barrel. This is not ideal because of the air space. One way around this is to inject co2 until air escapes through the pressure relief valve, which to some extent will purge oxygen.

 

[tonyhibbett]

The cask is losing water at 50 ml per day, even with humidity of 74%. That's 1.5 litres per month and a gallon every 3 months. There is no leak and the bung is watertight. So I will varnish both ends.
The small casks containing white wine are attracting fruit flies around the bungs. They are not seeping, so it must be vapour which is attracting them.
I have cleared out the remaining bottles of 2015 pinot noir from the bin in the shed, labelled them and used them to replace the empty bottles in the racks. There are enough empties for the wine in the pressure barrel, so once full, I can put them in the now vacant bin in the shed.

 

[tonyhibbett]

Time to compare the current vintage with the previous (2015). The older one is good. Deep red, smooth on the palate, balanced acid and tannin. A bit old fashioned, needing to breathe at room temperature before drinking and with a bit of crusty sediment. English Burgundy - something I've been trying to produce for years, and plenty of it.

 

[tonyhibbett]

I checked the levels in the five 20 litre casks and found each required a 200 ml top up. That's 1% in just 12 days. At that rate I will need about 3 litres of topping up wine per month to keep them full! However, maturation should be complete in 6 months with this size of cask. Nonetheless a total of 18 litres would be required for topping up all 5 casks over that period.

 

[tonyhibbett]

Rather than maintain the wine in the smallest barrel, I racked 3 litres into 3 Sodastream bottles and the rest into normal wine bottles, then put them all into the freezer to chill with a view to carbonation. 13 bursts of co2 is more than enough to make the wine sparkling. It's then poured through a small funnel down a tube which reaches the bottom of a sparkling wine bottle, which is then closed with a stopper and secured with a wire cage. This is entirely cosmetic, as an ordinary screw top bottle can hold the pressure, but may leak if stored on it's side. This holds only 800 ml, so the litre bottle is topped up with wine from the ordinary bottle and the process is repeated. I got 6 full bottles plus enough left over for 2 glasses. It didn't taste anything like as good as the 2016 bottle fermented version, so I will leave it to mature.

 

[Dutto]

........ That's 1% in just 12 days. ............

I had a lot of problems getting my little barrel to seal but what did the trick in the end was to stick boiling water in there and then keep topping it up with water to keep it full to overflowing for two weeks; and then repeat the process for another two weeks!

It didn't stop the losses completely, and even now (25 years later) it still loses a bit. However, I can recommend perseverance because the taste is that much better and there is the added bonus that only the drinker knows how much is being consumed!

 

[tonyhibbett]

After 25 years it won't be imparting any oak flavour as such, but the slow breathing that occurs gives some benefit.

 

[mlcrh]

I've got a wee 5L oak cask into which i put some home distilled spirit (because there's no biofuel like oak matured biofuel Mr Exciseman). I was worried with such a small cask about evaporation so i covered it in a thick layer of bee's wax before leaving it for around 2 years. Even with a layer of wax a mm thick everywhere i still lost half the whiskey to the angels. The three and a bit bottles that made it through the process are very good with a lovely honey scent imparted from the wax and are now precious stuff.
In considering the surface area to volume ratios of my cask and those used in the whiskey industry i estimate i have the equivalent of a 30 year old single malt.
There is some elderberry port in the cask now but using to improve cheap whiskey is a bloody good idea Dutto, and considerably less faff than distilling it myself. Although i do love a bit of extra faff sometimes in my brewing.