craft whiskey distilling

8/3/2019 Craft Whiskey Distilling

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AmErICAn DIstIllInG InstItutE | 1

Distillation Principls

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2 | CrAFt WHIskEy DIstIllInG




HOw DISTILLATION wORkS

Distillation is a physical procss whr compounds ar sparatd by virtu o thir dir-nt boiling points and vapor prssurs.

Th sparation in distillation occurs whn a mixtur o compounds in th still is broughtto boil. As a simplifcation, assum that th still contains only thanol and watr. Ignoring

th azotrop discussd blow, or vry mix ratio o thanol to watr thr is on andonly on nw boiling point that lis btwn th boiling point o ithr. Convrsly, orach boiling point, thr is on and only on ratio o thanol in th kttl, and an nrichdratio in th vapor and th distillat. I you know th tmpratur in th kttl, you can lookup th xact thanol ratio both in th kttl and in th vapor/distillat, in a simpl tabl[fgur 1/pag 5].

Assum a mixtur o 90% watr and 10% thanol (by volum) is to b sparatd by dis-tillation. Watr has a boiling point o 212ºF and thanol has a boiling point o 173ºF, butthis 10% thanol mixtur will boil at 197ºF; it will not boil at 173ºF. Th vapor abov thliquid will b 61% thanol, as will th distillat. In a simpl kttl, th thanol prcntagwill drop during th boil bcaus mor thanol than watr is bing rmovd, and nithr

ar bing rplnishd. This alon accounts or th incras in boiling point rom start tofnish— th ratio changs, so th BP changs.

Not that w startd with 10% thanol in th kttl, and now hav a distillat at 61%thanol, a 6-old incras in strngth. Rrring to th tabl and graph blow, i w nowdistill this condnsat again, th nw distillat will b 86%, and i w distill that, w willhav a 91%, and again 92%, and again 93% and atr six distillations, w may gt 94%. As thconcntration o th impurity (watr) dcrass, it bcoms mor difcult to rmov. This

Most artisan stills are o the refux or pot columndesign because o the inherent fexibility that they oer.




notion is vry important or othr products o rmntation in our wash. No mattr whatth concntration and boiling point o a givn impurity, som o it will scap th kttland fnd its way to th distillat throughout th distilling run. This mans that had cutscan nvr b prcis bcaus ths lightr impuritis do not all vaporiz bor th hartsbgin. Likwis, som tail impuritis manag to vaporiz wll bor thy ar xpctd.Compounds with boiling points btwn watr and thanol, such as diactyl at 190ºF mayb impossibl to rmov by distillation. Thror, distilling a bad wash nvr maks agood whisky— and a good whisky always starts with a good wash.

High-sparation vodka stills mploy a rux column with many plats whr vapors cancondns, thn lik small kttls, r-vaporiz th nw nrichd liquid, urthr nriching thvapor. Multipl cycls o condnsation and r-boiling, on cycl pr plat, occur in a singl

pass as vapors ris through th column bor distillat is drawn rom th still nar thtop. evn ths stills can not nrich byond 96.5% ABV bcaus thanol and watr orm anazotrop whr som mix ratios hav a boiling point not btwn th boiling points o thconstitunts. This prvnts complt distillation. Nonthlss, rux columns attachd topot still can sharpn sparation, making had and tail cuts asir, but most bliv thatthis lads to a lssr whisky bcaus th clanr sparation strips away charactr. Artisandistillrs want to prsrv th charactr o thir whisky, so i a column is mployd, thplats ar opnd to rduc rux and mor closly match th rsults rom th nck andarm o a traditional whisky still.

I your kttl tmpratur is 198.5ºF thn your kttl contains 9% thanol and th vaporcontains 59% thanol. As th run gos on, thanol is rmovd rom th kttl, th kttl

tmpratur riss toward 212ºF and th vapor concntration dcrass.

THE DIFFERENT TypES OF STILLS

Thr ar a numbr o dirnt dsigns o stills. Th most basic dsign is a “pot still,”with a pip lading rom th lid into a condnsr coil. Th condnsr coil can ithr b longnough to air cool th vapors or it can b shortr and immrsd in a watr jackt. Such astill aords minimum sparation sinc thr is almost no sparation o th vapors oncthy lav th boilr. Although this dsign o still is not suitabl or producing bvragalcohol by modrn standards, it will still concntrat an 8 or 10% abv wash to 60% in aairly ast run.

Th nxt typ o still is th “whisky still,” somtims calld a “goosnck still.” Thisdsign is tchnically a orm o pot still and has bn in us or cnturis or commrcialwhisky production, and is just as popular today in modrn whisky distillris as it hasvr bn. A whisky still has a larg boilr with a long broad nck rising rom it. Thnck bnds at th top and lads to a condnsr coil immrsd in watr. This dsign is vrysimilar to th crud pot still, xcpt th tall broad nck aords nough sparation to holdback most o th usl alcohols rom th distillat whil rtaining th dsird avors in thfnishd spirit. Thy ar suitd to th production o whisky, brandy, rum, schnapps, and




othr non-nutral spirits, or which thy ar vry widly usd commrcially. Howvr, thwhisky still is not suitabl or th production o vodka, gin, or othr spirits drivd romnutral alcohol, which rquirs a high-sparation still capabl o producing pur thanol.

This brings us to th high-sparation still dsign calld a “column still” or a “ractionat-ing still.” A ractionating still is usd to produc pur thanol by ractional distillation orvodka and gin, or or pharmacutical and laboratory us.

[Fige 1] thi i a abe ad gaph of boiig poi fo ehao/wae ixeb voe. (Hi— cop hi ad pae i oo o i).




In smallr ractionating stills th vapors mrging rom th boiling mixtur pass up acolumn packd with small pics o glass, cramic, stainlss stl, coppr or othr matrial,inrt to th procss. This matrial is calld th “column packing.” In largr ractionatingstills, th columns hav ba plats with hols or bubbl caps instad o packing matrial.each pic o packing, or bubbl cap, can hold a small amount o liquid, ithr intrnally(i thy hav intrnal crvics) or in th intrstics btwn adjacnt particls. At th topo th column, th mrging vapor is condnsd into a liquid by mans o a hat xchangrwith cold watr running through it. Th condnsd liquid runs back down th columnuntil it rachs th boilr whr it is rhatd, convrtd into vapor onc mor, and oncagain movs up th column.

At quilibrium, which taks about an hour to achiv in th cas o pur-thanol produc-

tion, th systm consists o vapor rising up th column mting a ow o liquid runningdown th column rom th hat xchangr. At ach vapor-liquid intrac on th packingmatrial within th column, a partial sparation occurs whrin th mor volatil compo-nnts o th mixtur go into th vapor phas and ris whil th lss volatil componnts gointo th liquid phas and ar carrid down toward th boilr. At quilibrium, th variouscomponnts in th mixtur bcom stackd up in th column in th ordr o thir boilingpoints, th most volatil at th top and th last volatil at th bottom.

Thr’s a variation o ractionating still calld th “continuous-run still.” With th con-tinuous-run dsign o ractionating still, th rmntd wash is d into a small boilingchambr rom a rsrvoir and is vaporizd immdiatly upon ntry to th chambr. Thdirnt componnts o th mixtur ar drawn o at various hights along th column,

and th spnt rsidu is draind o at th bottom. This procss can continu indfnitlyas long as rmntd wash is d into th boiling chambr. Acton, or xampl, would bcontinuously drawn o rom th top o th column whil thanol would b continuouslydrawn o rom a point a littl urthr down.

Th last still dsign to b discussd in this txt is th “rux still.” A rux still is vrysimilar in dsign to th ractionating still xcpt it dosn’t hav a hat xchangr at th topo th column orcing a complt condnsation o all th vapor that rachs th top. It hasa packd column lik a ractionating still, but th vapor that rachs th top xits to thcondnsr and is rcivd as output. Whil a rux still bnfts by th puriying procsso th rdistilling at th packing suracs lik a ractionating still dos, without th orcdrux o a top hat xchangr it dosn’t produc as pur a nutral thanol as a ractionat-ing still. Howvr, rux stills ar vry commonly usd in th artisan distillation o whisky,and othr non-nutral spirits, and it’s this typ o still that will b discussd in th rst o this txt.

Most artisan stills ar o th rux or pot column dsign bcaus o th inhrnt x-ibility that thy or. Th bst known manuacturrs o pot and rux stills ar: Vndom,Holstin, Christian Carl, and Forsyth. Th Indx contains a complt list o manuactur-




rs. Ths brands o still com with multipl bubbl-cap trays, and ach tray can b by-passd by oprating a lvr. Ths stills can also b purchasd with a dphlgmator, whichis a chilling apparatus at th top o th column comprisd o a bank o tubs with coldwatr running through thm to incras th rux, and thror th purity o th distil-lat. Th still can b opratd with th dphlgmator disabld, or with cold watr runningthrough it at whatvr rat th oprator chooss. Btwn th variability o th dphlgma-tor and th ability to bypass, or not, th multipl bubbl-cap trays, just about any lvl o sparation can b achivd with ths artisan stills. That’s why thy mak such xcllntwhisky stills.

THE FLAvOR OF SHApE

Th whisky still has our parts: pot, swan nck, lyn arm, and condnsr. Th shap o ach sction acts rctifcation and th tast o th spirits. Thr atd (to 172º). It can bhatd by dirct fr, stam, gas, or wood. All systms hav advantags and disadvantags.Thr is no right way to hat wash. Most manuacturrs, howvr, prr a doubl-jacktdstam-watr systm that provids a gntl hat to th wash. Mainly, you don’t want toburn th wash. Most pots hav a sight glass so th distillr can chck or oaming duringth distillation procss.

n Th swan nck sits on top o th pot. It can b tall, short, straight, or taprd. Otn thswan nck is connctd to th pot via an og, a bubbl-shapd chambr. Th og allowsth distillat to xpand, condns, and all back into th pot during distillation. Most potstills hav a taprd swan nck, allowing or bttr sparation and bttr nriching o th

spirits during distilling.

n Th lyn arm sits on top o th swan nck. It can b tiltd up or down, and it can btaprd or straight. Most arms ar taprd down. Otn pot stills ar fttd with a dphlg-mator, or what th Scots call a purifr. Th dphlgmator is fttd with bas that uswatr plats or tubs to cool th distillat, snding 90 prcnt o it back to th pot. Its mainpurpos is th nrichmnt o th spirits bor thy’r snt on to th condnsr.

n Th condnsr, or worm is usd or cooling th spirits and providing a small stram to acollction tank or pail.

DISTILLATION pROCESS

In distilling parlanc, th compounds in th wash that ar not thanol or watr ar calldcongnrs. Som congnrs such as actaldhyd, mthanol, and crtain strs and ald-hyds, hav boiling points lowr than thanol, whil crtain othr strs, th highr al-cohols (usl alcohols), and watr, hav highr boiling points than thanol. This mansth lowr-boiling-point congnrs com out in high concntration at th bginning o thdistillation run, and th highr-boiling-point ons com out in high concntration towardsth nd o th run, laving th thanol as th most abundant compound during th middlo th run.




So, whn distillation taks plac in an artisan still, such as th rux stills discussdabov, th distillat that coms out is dividd into thr phass calld: hads, harts and,tails. Th hads contain th unwantd lowr-boiling-point congnrs that com out at thbginning o th run, and th tails contain th unwantd highr-boiling-point congnrsthat com out at th nd o th run. And, th harts ar th dsird spirit.

Sinc whisky is not distilld at a high-sparation lvl, it mans that ach phas bldsinto th adjacnt phas. That is to say, thr‘s a considrabl amount o thanol in thhads phas, and thr ar lat hads congnrs at th bginning o th harts phas. Simi-larly, thr ‘s a signifcant amount o arly tails congnrs at th nd o th harts, and thr‘s a considrabl amount o thanol in th tails phas. Th harts ar th whisky, and whilthy ar comprisd mostly o thanol and watr, thy hav a dlicat balanc o lat-hads

and arly-tails congnrs that mak up th avor profl o th whisky.

Sinc both th hads and th tails contain a lot o thanol and rsidual dsirabl avor,thy ar mixd togthr and savd or utur rcovry. Th hads and tails whn mixd to-gthr ar calld ints. Thy can b distilld sparatly to produc anothr whisky run, orthy can b mixd in with a utur spirit run, whr thir thanol and avors ar rcovrdas a part o that run. Howvr, ach subsqunt distillation producs its own st o hads,harts, and tails, and th ints rom thos runs ar also savd or utur rcovry.

Whn whisky is mad, it’s usually don in two distillation runs: a br-stripping run;and, a spirit run. Th br-stripping run is gnrally don in a largr, high-volum potstill calld a br strippr. Th br strippr is usd to distill th rmntd mash and con-

cntrat th thanol and all th impuritis into a distillat o about 35% thanol, calldlow-win. Th spirit-run is don in a smallr whisky still, ithr a goosnck or an artisanrux still, calld a “spirit still.” Th spirit still is usd to distill th low-win and rfnthm into th fnishd spirit. Thr ar th two outputs rtaind rom th spirit-run: thfnishd spirit; and, th ints

For a br-stripping run, th rmntd mash, which is typically about 8% abv, is loaddinto th br-strippr, and th contnts ar brought to boil. Sinc this run is just a primarydistillation, th hads, harts, and tails ar not sparatd out. Th ntir output rom thisrun is collctd in a singl lot, and th run is continud until th aggrgat prcnt alcoholis down to 35% abv. This distillat is th low-win, which is th input to th spirit run.

To produc th fnishd whisky, th spirit still is flld with th low-win rom th br-

stripping run, and otn a masur o ints rom prvious spirit-runs. Th spirit still isthn brought to boil. It is with th spirit run that th distillr adjusts th boil-up rat toachiv a gntl, slow ow o distillat and carully sparats out th hads, harts, andtails.

Som whisky distillris produc thir whisky in on singl distillation. In ct, thydo a spirit run dirctly rom th wash. Th artisan rux stills discussd abov ar xcl-lntly suitd to doing this typ o whisky distillation, but oprationally it’s vry labor in-




tnsiv and a lot o attntion must b paid by th distillr to numrous smallr runs rathrthan on largr run.

Som popl fnd th whisky rom a singl distillation run to b richr and to hav amor natural avor, whil othrs fnd it to b harsh and unrfnd. In this txt, th mor-common doubl-distillation mthod is usd.

MAkINg THE CuTS

Probably th most lusiv part o th distilling procss or making whisky, is makingth cuts rom hads to harts and thn to tails. Making a cut rom on phas to th nxt isth point whr th distillr switchs th output so that itís collctd in a dirnt rcivrthan th prvious phas. At th nd o th spirit run, th hads will b in on containr,

th harts in anothr, and th tails in a third on. Th qustion is, whn to switch rom onphas to th nxt?

exprincd distillrs do this by tast. evn though thr ar masurabl paramtrslik still-had tmpratur and prcnt alcohol o th volving spirit that can b usd to

judg whn to mak th cuts, tast and smll still rmain th most rliabl mthod o d-trmining thm.

Th mpirical paramtrs or judging th cuts ar: th prcnt alcohol o th spirit that’sowing out o th still (i.. th volving spirit); and, th still-had tmpratur. Howvr,ths vary rom on still to th nxt, and vary basd on th proprtis o th low-win (.g.,prcnt alcohol, and quantity). It is possibl to dvlop a consistnt procss using th sam

still and th sam quantity and a ormulation o low-win, such that th paramtrs rmainth sam or ach run. For xampl, i a spirit run is bing don in an artisan rux stillwith low-win that is 35% abv, th bgin-cut (i.. th cut rom hads to harts) is usuallydon whn th volving distillat is at about 80% and whn th still-had tmpratur isabout 180 dgrs. And, th nd-cut (i.., th cut rom harts to tails) is otn don at about65% and whn th still-had tmpratur is about 200 dgrs. Howvr, a spirit distilldrom a straight malt wash, can otn b nd-cut as low as 60%. It’s bcaus o ths nuancsthat smll and tast bcom th only truly rliabl indicators o whn to mak th cuts.

Whn making th bgin-cut, th tast charactristics that th distillr is looking or aras ollows. Whn a spirit run coms to boil and th frst d istillat starts owing rom thstill, this is th bginning o th hads phas. Th distillr can collct a small sampl o th

distillat on a spoon or in a win glass and smll it. At this stag, th distillat will hav thsickning smll o solvnts lik nail polish rmovr or paintbrush clanr. Howvr, borlong this solvnt smll will diminish, and vn whn a sampl is tastd ths compoundswill b vry aint. As th solvnt charactr disappars compltly, th distillat will start totak on a hint o whisky avor. This avor will incras until it bcoms vry pronouncdand highly concntratd. It’s whn this avor is clarly vidnt (i.., mor than just a hint)but is still incrasing in intnsity that th distillr cuts to th harts phas.




To mak th nd-cut th distillr nds to monitor th avor o th harts through thollowing changs in tast. At th bginning o th harts phas, th intnsity o th whis-ky avor will still b incrasing, and will continu to do so until it bcoms vry strong.Howvr, as th harts continu, th intns whisky avor will ad into a smooth, swt,plasant avor that will prsist or most o th harts. Th avor will chang slightly as thharts progrss but it will rmain swt and plasant. Towards th nd o th harts, thavor will start losing its swtnss and a trac o harsh bittrnss will bing to appar inth avour. This harsh, bittr avor is th onst o th tails. Whil a small amount o thisbittrnss is considrd to contribut to th “bit” charactr o th whisky, th distillrshould cut to th tails rcivr bor mush o it is allowd to ntr th harts.

Th tails can b collctd until th volving distillat is down to about 10% and th still-

had tmpratur is about 210 dgrs. Th rason or doing this is to rndr all th r-sidual alcohol that’s lt in th still at th nd o th harts phas. This alcohol can thn brcovrd in a utur spirit run.

Th tails phas starts out bittr, and th bittrnss bcoms mor intns as th tailscontinu, but as th tails progrss, th bittrnss subsids and givs way to a swt-tast-ing watr. This swt watr is calld “backins.”

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