Costly cask conditioning

[tonyhibbett]

2 years ago I bought a 5 litre new oak cask. After the usual soaking and cleaning, I filled it with a 'port' made mostly with expired and leftover ingredients and fortified with various leftover spirits. New oak needs a certain amount of weathering to make it watertight, especially the wooden tap, so I left it outside. For a while, I monitored the level and topped up with a mixture of wine and cheap vodka. The tap continued to leak for ages and I gave up bothering to monitor the level. Today, I removed the bung and siphoned out the contents, a mere 3 bottles - less than half the original contents! Most of the loss was due to the tap which did finally stop leaking, but a fair amount had been soaked up by the wood. The port tasted excellent. I rinsed out the small amount of sediment and filled up with my new pinot noir, which I will leave probably no more than 3 months, leaving the rest in a polypin with oak chips, for comparison.
I had originally ordered a 20 litre cask, but the supplier was out of stock, hence the 5 litre one, which they had. The 20 litre one never materialised, as the supplier went out of business. I have now found an Italian supplier, who sells an 18 litre cask, complete with stand, bung and a steel tap (non-leaky) for £80, plus £20 delivery. The capacity is nominal and also increases when swollen with liquid, after a time. This is expensive compared to a 20 litre polypin which I can get for £18 post free, plus £2 for oak chips!

 

[dennisking]

You can get the polypins even cheaper

 

[tonyhibbett]

Looks somewhat flimsy. Have you used them? How much is delivery?

 

[tonyhibbett]

Meanwhile, I checked the level in the cask. It required topping up with 40 ml. As there was no sign of a leak or seepage, I assume that the wood is rehydrating, having been left half empty for a very long time. It is interesting to note that such a large air space had no ill effect on wine. Also the surface area of oak (5 litre cask) in contact with the wine, when full, is the equivalent of 16 g of 'chunky' oak chips. That would be 64 g for a 20 litre polypin.

 

[Tim_Crowhurst]

Also the surface area of oak (5 litre cask) in contact with the wine, when full, is the equivalent of 16 g of 'chunky' oak chips. That would be 64 g for a 20 litre polypin.

What would the oak chip equivalent of a 225L/50 gallon or 300L/67 gallon barrel be? There would be less contact with the oak, so a less pronounced effect. The Ardbeg distillery (I think it's Ardbeg) recently started producing a whisky that is matured in smaller barrels to boost the effect of the barrel on the flavour.

If you wanted to scale up the 5L cask effect to a 50 or 67 gallon barrel you'd be looking at either 720g or 960g of oak chips, but that's not including the oak of the barrel itself so would only work on a steel barrel (or similar).

Not that I ever hope to be able to produce that much wine in one batch, of course! I'm just curious.

 

[dennisking]

Looks somewhat flimsy. Have you used them? How much is delivery?

I've been using the same or similar over 30 years you would surprised how much pressure they take. Don't know the postage I get mine locally, the do have free postage on a lot of items.

 

[tonyhibbett]

Interesting about using smaller barrels. The difference in price between a very large barrel and a small one is very small, due to labour cost and losses due to evaporation are greater as the size decreases. For the amateur, 4.5 gallons would seem to be the optimum. I have one the next size up, 9 gallons, which is too heavy to handle when full and I only once had enough wine to fill it, so the question is somewhat academic!

 

[tonyhibbett]

I miscalculated the amount of chips to provided the same surface area of a 5 litre cask. It's 60 grams. For 20 litres, about 190 grams. 60 x 4 = 240, so the smaller the cask, the greater the contact of the wine to the wood. A 20 litre cask has about 25% less than the 5 litre. If my calculations are correct, then the typical dose of 10-60 grams per 20 litres falls far short of an oak cask, and a polypin does not 'breathe' which is an important part of the maturation process.
Overnight the level of wine fell by only 15 ml, compared with 40 in the previous 24 hours, which is good news.
The only way I can make use of my 9 gallon cask (which actually holds 10 gallons) is to make 2 x 5 gallon brews and combine them.

 

[tonyhibbett]

The level has dropped a mere 8 ml, a promising trend.
As far as I can work out, increasing capacity by 4, from 5 l to 20, reduces the surface area by about 25% proportionally. Going up to the next size, the 9 gallon firkin, this reduction becomes 50%, I assume, but this can't be right, as you would soon get to 100%, which is nonsense!

 

[Tim_Crowhurst]

This has had me puzzling all afternoon, and I've finally figured out why.

Firstly, if you multiply up from a 5L cask to a 20L cask you are multiplying by 4. This means the 40L firkin is not the next step in the sequence, it's an 80L kilderkin (half a beer barrel, two-thirds of a wine barrel).

Secondly, any container with twice the dimensions of another container the same shape will have eight times the volume, because two cubed is eight, so the firkin should have twice the internal dimensions of the 5L cask. The surface-volume ratio halves every time you double the container's dimensions (and therefore octuple it's volume) so the firkin does have a ratio that is 50% that of the 5L cask.

In addition, when you work out the ratio for the next container in the sequence, you work it out based on the container you're currently on, not the original container. So the next container in the sequence (a 320L puncheon) has a ratio half that of a firkin, so one-quarter the ratio of a 5L cask. The next volume in the sequence, 640L (about two-thirds of a tun) has a ratio half that of a puncheon, a quarter that of a firkin, and one-eighth that of a 5L cask.

I won't go into the maths, because it's complicated and has already taken the last of my sloe gin to figure out, but this means the ratio drops by roughly 20% every time you double the volume (5L to 10L) and about 37% if you quadruple it (5L to 20L). So your 20L cask will have a surface-volume ratio that is about 63% (not 75%) of the ratio of the 5L cask.

 

[tonyhibbett]

I have finally grasped the secret of casks. My first (old) one leaked when full of wine, so I gave up on it. The same happened with the new one. Now they are both watertight, because the wine and weather conditioned them, so that when refilled, they are fine, even the notorious wooden taps, which are in fact of no use at all for dispensing wine. The sole function of the wooden cask is bulk maturation, mostly for red wine. You fill them, leave them with periodic checks and when you are happy with the wine, you siphon it out into bottles, or a polypin, and fill it with the next batch, having rinsed out any sediment.
One cask is too big, the other too small, so I have ordered a 20 litre (pin) seasoned oak cask from thebarrelmakers for £95 including stand, bung, tap and delivery. It will take time to get it into shape, but this time I intend to get it right. The plan is to get a cheap 30 bottle wine kit and ferment it in the cask. The yeast will plug all the cracks and crevices while the must will interact with the young oak and probably produce a rather harsh and unpleasant wine, so any initial losses from leakage will be of no consequence or concern. Thereafter, the cask will be good for many years. If this strategy works, I will buy another cask and so on.

 

[tonyhibbett]

It will take me time to absorb all of that maths, which is not my strong point. I coped with old money more with the language than the maths. 2 farthings made a hapeney, 2 of them made a copper, 3 of them made a thrupenny bit, 2 of them made a tanner, 2 of them made a bob, 2 of them made a florin, 2 and a half of them made half a crown, 4 of them made a ten bob note or half a knicker, 2 made a quid, 21 shillings made a guinea, a unit in which I was once paid. Occasionally you got to handle a fiver, but a tenner was only for the rich and banks were an alien world. Decimalisation simply pushed up prices and vat pushed them up further. That was obvious. But the problem of coinage has not been solved. I still end up carrying enough shrapnel in my pocket to cut a hole in it.

 

[bobsbeer]

Good luck with your casking efforts. Sadly I don't have the storage for casks or I might be tempted. Even if it was to put kit red wine in. As for LSD I remember them well. I thought I was rich if I had a sixpence, never mind a shilling. :lol:

 

[tonyhibbett]

Bit tricky this tangent. As a student, I had to supplement my income to support my flat, girlfriend and motorbike. My close friends of the time now deny my existence but I was also making wine during this period!

 

[bobsbeer]

...I had to supplement my income to support my flat, girlfriend and motorbike....but I was also making wine during this period...

Oooooh I say. Good entrepreneurial spirit.

 

[tonyhibbett]

Meanwhile, the level has dropped only 5 ml. Some evaporation is inevitable and the price you pay for maturation benefits of the breathing. Since I assume that the rate of evaporation relates to the surface area, the losses will be proportionately higher the smaller the cask, but the maturation period will be shorter. I have read that the best reds are stored for so long, the casks become 'exhausted' and are sold off for other purposes, or used again for lesser wines. The cost for me would be prohibitive, because I am using relatively small casks, whereas much larger casks cost little more than them, eg 100 litre size for £109. Therefore my old firkin will need at least 100 g. of fresh oak chips added to restore its 'potency'.

 

[tonyhibbett]

Evaporation has stabilised at 5 ml per day. This suggests that it took 4 days for the cask to fully rehydrate.
That's about 500 ml over 3 months, 10% of 5 litres. What gets lost is water and alcohol only, so the body of the wine should improve. But at that rate 80% should have been lost over 2 years, when in fact it was only 55%. I assume that as the level drops, so does the area of the wine in contact with the wood, so the rate of evaporation gradually decreases. Another factor is that the port was high in alcohol (20%) and sweet, making the wine significantly thicker and thus slowing down the evaporation rate.
Looking at the 50 litre cask, filled only with water, the loss is already now down to 40 ml per day, a rate 10% less than the 5 litre cask and probably still absorbing water and probably taking longer to do so because of the greater size.
So when the new cask arrives, it should soaked with water and topped up for 4 days to be fully hydrated. Initial losses thereafter will be purely water during the conditioning fermentation of what could well be made up of the remaining apples on the tree, of which there are plenty still. This would inoculate the cask with wild yeasts and lactobacillus to promote 'real wine', the logical follow up to real ale, to replace the sanitised bland offerings you may encounter at the more affordable end of the market.

 

[tonyhibbett]

The water loss from the firkin is now down to 30 ml per day, less than a litre per month. Wine is more viscous than water, so may evaporate more slowly. Humidity is the key. Water evaporates when the humidity is below 75%, whereas alcohol evaporated when it is higher than this. At the moment, the humidity is about 65%, only water would be lost from wine, which is of no consequence and actually improves the body and alcohol content of the wine. Temperature of course is another factor, particularly the dew point, the evaporation threshold.
Meanwhile the new 20 litre cask has arrived, with a broken stand, a tap too big for its hole and a capacity of only 18.6 litres. The stand was easily fixed with wood glue, a cut down synthetic cork plugged the tap hole and hopefully the capacity will increase during initial soaking due to swelling. We shall see after 48 hours.

 

[tonyhibbett]

The new cask did not expand much. It is obviously made as a 4.5 gallon 'pin', not a true 20 litre cask. As such, kit wise, probably best suited to the 21 litre Cellar 7 and Cantina so-called 30 bottle kits, which end up closer to 19 litres, and any surplus can be used for topping up the cask.
An interesting development with the 5 litre cask. I took a sample from it and injected it into the topping up bottle, to top it up. The wine instantly fizzed, suggesting that a malolactic fermentation was taking place either in the bottle or in the cask, or possibly both and possibly in the polypin too! Either way, it is now taking place in the bottle, so any further topping up of the cask will inoculate it with the lactobacillus i it's not there already. Unlike a screw top bottle, any pressure from the co2 gas generated from mlf will be diffused due to the porosity of the wood, and particularly the wooden bung. Well that is theory. I just checked and instead of the volume reducing, it is now forcing its way out through the sides of the bung! I have installed a rudimentary valve to let the gas escape. Clearly the mlf is occurring in the cask.

 

[Tim_Crowhurst]

The new cask did not expand much. It is obviously made as a 4.5 gallon 'pin', not a true 20 litre cask. As such, kit wise, probably best suited to the 21 litre Cellar 7 and Cantina so-called 30 bottle kits, which end up closer to 19 litres, and any surplus can be used for topping up the cask.

It would also be ideal for short-brewing other 30-bottle kits.