Books on barrel aging?

[Penrock Distillery]

Hi All
I'm considering my future corn whiskey barrel aging program and was wondering if there are any books etc on how the spirit develops in flavour within the barrel as it ages?
I know there are a million factors that can influence how a spirit ages, but I was after a description of how the flavour profile develops as the spirit sits in the cask.
Ideally Id love to find descriptions for small casks, as always, Its about how I can get the best whiskey to market as quickly as possible in the early stages.

Many thanks for your time to read this post
Regards Sim

[Silk City Distillers]

Here's one of the best pieces of research I've ever seen on small barrels.

AGING-OF-WHISKEY-SPIRITS-IN-BARRELS-OF-NON-TRADITIONAL-VOLUME.pdf

[Penrock Distillery]

You my friend, are a star. !!! Thank you. I'll have a read and try to digest. !!! It certainty looks detailed from first glances.

[Silk City Distillers]

No prob.

My own 2 cents, which admittedly might not even be worth that, is that anything below 15g isn't worth anyone's time.  I'm sure I'll upset people using barrels smaller than that, but in our experience, the extraction curve crosses the maturation curve far too early below 15g.  We played around with 10g and 15g, and now only use 15g for our test batches, with the intent on 12-18m aging on the test batches.  We find this to be far superior than pushing a 10g to the 12 month mark, or dumping at 10g earlier than one year.  To us, 15g feels like the tipping point between small cask and large cask.  One thing to keep in mind for us, we're in a fairly dry climate during the winter, and our barrel storage is conditioned (read: very dry), so we typically see substantial evaporations - 10% a year is typical for us in smaller cooperage.  If you are cooler, and wetter, you might be able to stretch out the maturation time before over-oaking.  Our go-to now is 30g, and we're currently transitioning to 53g - which means laying down a lot of inventory (and needing lots of space).  I think the Kelvin 25g size is a nice balanced position if you needed to be slightly smaller, it's a manageable size, and we had some good results at the 2 year mark.  Barrel Mill 15/30g have been winners for us.

Used cooperage is another story entirely, we've found second and third fills on small barrels to work well with dark rums aged far longer than you would ever realistically consider in a first fill small cask (~1 month per gallon as a rule of thumb).  We have some high ester rums at 2 years in second fill 10g that are fantastic.  Depending on your jurisdictions, you might have better success with second-fill small cooperage whiskies aged longer.  We don't have this option in the US.

[Silk City Distillers]

From the conclusion above:

Quote

It was noted that the 2 and 3 gallon barrels were over extracted and their sensory qualities were poor. Other barrels in the series tasted over extracted at certain points but by the end of the study at day 270, both 5 and 10 gallon barrels had developed some characteristics of mature whiskies and their sensory qualities had begun to improve. While this is a subjective judgment of the author, samples were compared to industry products and found to have some qualities in common that had been lacking at previous time points. This is an important feature as it points to the fact that while extraction is an important process, time is required to incorporate the extracted compounds into the spirit to produce maturity.  It is also important to note that while over extraction is possible, even higher than normal concentrations of extractives may be fully integrated into the spirit given enough time.

Don't forget about the small barrel maturation curve, it goes like this:

1. Young harsh distillate.

2. Tastes faintly like whiskey.

3. OH MY GOD ITS OVER-OAKED.

4. Wow, that's really good, I now realize that #2 tastes terrible.

5. Ah christ, now it's really over-oaked.

6. Garbage.

Many pull at # 2, on the upswing of the extraction curve. I feel this is incorrect, misleading. You generally see these as products aged 6-8 months in 10 gallon. What you get it extraction products and color without maturation products. Bitter/Dry Tannin is on the upswing, peaking in # 3. But, it's not until these have some time to oxidize/react, settle down, allow the vanillin/syringealdehyde to come through.

For us, # 4 is 12-14 months in a 10 gallon. # 5 if about 15-16 months.  You may have some luck "rescuing" #5 by dumping into stainless tanks with plenty of headspace and letting it sit for a few more months.  You will never "rescue" #6, it's not even suitable for blending.

Or just bite the bullet and push to 15/25/30g sizes.

Quote

Further study would be useful for the elucidation of the total aging process in alternative barrels. For this, the use of a concentration and extraction method might be necessary to examine concentrations on a longer time scale. Because of the large angel’s share from 2 and 3 gallon barrels they must be considered unfeasible for use in industry for anything other than rapid examination of certain oak characters in trial whiskies. As such, barrels of 10, 20, and 30 gallons might be examined for extraction and aging character and in the context of the larger barrels, larger samples appropriate to extraction and concentration would be possible.

 

[bluestar]

1 hour ago, Silk City Distillers said:

No prob.

My own 2 cents, which admittedly might not even be worth that, is that anything below 15g isn't worth anyone's time.  I'm sure I'll upset people using barrels smaller than that, but in our experience, the extraction curve crosses the maturation curve far too early below 15g.  We played around with 10g and 15g, and now only use 15g for our test batches, with the intent on 12-18m aging on the test batches.  We find this to be far superior than pushing a 10g to the 12 month mark, or dumping at 10g earlier than one year.  To us, 15g feels like the tipping point between small cask and large cask.  One thing to keep in mind for us, we're in a fairly dry climate during the winter, and our barrel storage is conditioned (read: very dry), so we typically see substantial evaporations - 10% a year is typical for us in smaller cooperage.  If you are cooler, and wetter, you might be able to stretch out the maturation time before over-oaking.  Our go-to now is 30g, and we're currently transitioning to 53g - which means laying down a lot of inventory (and needing lots of space).  I think the Kelvin 25g size is a nice balanced position if you needed to be slightly smaller, it's a manageable size, and we had some good results at the 2 year mark.  Barrel Mill 15/30g have been winners for us.

Used cooperage is another story entirely, we've found second and third fills on small barrels to work well with dark rums aged far longer than you would ever realistically consider in a first fill small cask (~1 month per gallon as a rule of thumb).  We have some high ester rums at 2 years in second fill 10g that are fantastic.  Depending on your jurisdictions, you might have better success with second-fill small cooperage whiskies aged longer.  We don't have this option in the US.

Certainly not upset. Just think your conclusions might be overreaching, and could be wrong in specific cases. We have experimented with 5, 8, 10, 15, 23, 30 gallon barrels, all chars, all toasts, different modifications (traditional, honeycomb, sliced, etc.). We also use 53g traditional in all chars. Our experience is that it VERY much depends on the barrel type, not just the size, as well as the type of spirit being aged. Even confining to whiskies, we found quite a difference in optimal choice for use of smaller barrels with malt barley, malt rye, and bourbon. With bourbon, it matters what the mash bill is. I would agree that using 5g (or smaller) is a real challenge for almost everything, although we have done so. For high-corn bourbon, we found 10g better than 15g or 23g, and definitely they will over oak in a short period of time. For this size, we particularly like the honeycomb, with very light char and good toast, for maximum vanillin extraction in a short time.  You CAN age through the over-oak period with a 10g or smaller barrel, but we found 2+ years necessary, and the extreme angel-share loss and concentrated extractives made these less interesting to drink on their own than to blend with larger barrels. For malt barley, would agree that 15g is a better minimum, but that also reflects the need to age 2+ years. Our preference in that case has been a light char, while using the same size for malt rye we preferred a heavy char and found 1+ years could work. The barrel we found the LEAST interesting was the 30g. We did not see much difference from using a 53g (not surprising, the difference in surface-to-volume ratio is very small). But something close to this size would have been traditional in the first part of the 19th century, and there is no reason to eschew it. We had used Barrel Mill in the past, particularly 15g & 30g, but lately have been using Black Swan exclusively for the small barrels, in part because Barrel Mill no longer makes one of the chars we found worked best for one of our whiskies, and Black Swan was more flexible with regard to special toasts and chars. But otherwise, we found Barrel Mill to produce barrels of high quality and good value. We agree that small barrels can be very interesting for aging in used barrels. This is particularly so when the barrels have only been used for short period aging, the quality of the spirit in the second use has some of the character more associated with aging in new char. One of our whiskies and a couple of our gins definitely owe their lauded flavor profile to that, we think. We also found them a good choice for aging brandy and are doing our first rum tests now.

Not really looking to argue against @Silk City Distillers observations, I think it is great to make their experience available to others here. I just wanted to add our own experience, especially where it might vary to some degree from others.

[Penrock Distillery]

Again, many thanks for your input, advice and help. I'll try to digest all the info. Cheers 🙂

[Silk City Distillers]

Not upset, we should be sharing more of this kind of information with each other - it's all good - I don't understand why we wouldn't leverage the knowledge of the collective to elevate everyone.

Compare this thread with a book on barrel aging published by a master distiller.  $35 for 150 worthless pages, without even a single actionable piece of information.

On another note, about bucking the trend.  We did some 1 year 100% Ryes in 15g, and 2+ in 30g - we still have customers today that beg us to lay down the 1 year rye (15g), they prefer it over the 2 and 3 year variants (30g).  The big difference is the fruitiness - big dark dried fruit and honey in the 1 year, it's nearly gone by 2, totally gone by 3, replaced with rye spice dominating.

[Silk City Distillers]

Quote

We agree that small barrels can be very interesting for aging in used barrels. This is particularly so when the barrels have only been used for short period aging, the quality of the spirit in the second use has some of the character more associated with aging in new char.

100%

[bluestar]

1 hour ago, Silk City Distillers said:

Not upset, we should be sharing more of this kind of information with each other - it's all good - I don't understand why we wouldn't leverage the knowledge of the collective to elevate everyone.

Compare this thread with a book on barrel aging published by a master distiller.  $35 for 150 worthless pages, without even a single actionable piece of information.

On another note, about bucking the trend.  We did some 1 year 100% Ryes in 15g, and 2+ in 30g - we still have customers today that beg us to lay down the 1 year rye (15g), they prefer it over the 2 and 3 year variants (30g).  The big difference is the fruitiness - big dark dried fruit and honey in the 1 year, it's nearly gone by 2, totally gone by 3, replaced with rye spice dominating.

We have a similar situation with our 100% malt rye whiskey, customers who still ask for the 1yo in 15g char 4, even though our standards are 2-3yo in 53g char 5 or 4 yo in 53g char 3. While it has a little more heat, it is sweeter with a bit more fruit and floral on the nose.

[Hudson bay distillers]

This is great info thanks guys for sharing your secrets . 

Tim

[Sator Square Distillery]

I've had very good results using #3 15g barrel mill cooperage with a 100% malted barley whiskey, 12 months in. Sells very well and I personally really love how it turns out.

[Foreshot]

The issue is that it's about chemistry. No book will be able to cover what you want to know. You're going to be searching for scientific papers like Silk City posted or experimenting. The chemistry of your spirits and the wood of the barrel and the effect of environment will yield different results. Learn to record observations really well. Keep track of as many variables as you practically can.

 

On 1/1/2020 at 10:04 AM, Silk City Distillers said:

Compare this thread with a book on barrel aging published by a master distiller.  $35 for 150 worthless pages, without even a single actionable piece of information.

That book was the biggest let down I've had. It really was useless.

[adamOVD]

On 1/7/2020 at 5:53 AM, Foreshot said:

That book was the biggest let down I've had. It really was useless.

What, you're not aging exclusively in floating pyramids now???

@Silk City Distillers and @bluestar thanks for sharing all you do on this forum. I'm thinking of using this slow (We haven't felt the covid pain too bad so far, but about two months ago things really started slowing down) time to transition to aging in 15 gallon barrels to 30s. Your insights on this post and others are super helpful.

Do those of you who have transitioned to a larger barrel think that if you double the barrel size, doubling the aging time is a good rule of thumb. I filled two 30s as test run, and tasted them at 6 months for the first time the other day, and I think seems about right, But I don't currently have a 15g at 3 months to do a side by side comparison. 

[Sudzie]

We always enjoyed our 30gals at around 18 months+/-  when we started out. But over the years and filling over 1000 30 gal barrels they are now hitting 3yrs and it’s now our sweet spot.  We’re going to let some go 4+ yrs (thanks COVID) to see how they do next year.   We also compare our 3yr 30’s against our 5 year 53’s and their definitely different and enjoy both equally.  We always save a case of each bourbon bottling and will do a horizontal tasting at some point in the future.  -Cheers

[Silk City Distillers]

We have noticed 30s being much more flexible with timing than 15s - far wider timing range, much less worried about letting them go longer.

[Sudzie]

9 hours ago, Silk City Distillers said:

We have noticed 30s being much more flexible with timing than 15s - far wider timing range, much less worried about letting them go longer.

Totally agree

[adamOVD]

Thanks everyone that's very encouraging. I'm in a hot dry climate, and I've been putting a pretty clean spirit in the barrel so I think 1 year might be enough. Hopefully, if we can build up an inventory, (and can handle it financially) I can slowly extend aging further and start playing around with putting a heavier spirit in the barrel.