Why is bourbon so sweet?

Credit: guzzphoto

Credit: guzzphoto

One unmistakable difference between bourbon whiskey and scotch whisky is the sweetness. You can come up with a variety of flavor profiles for any scotch whisky and “sweet” is unlikely to be one of them.

Floral and fruity are likely to be more accurate descriptors than sweet, especially when talking about anything finished in port pipes or another dessert wine.

But one sip of bourbon and the first thing that jumps to mind is its sweetness.

Bourbon is sweet. So very sweet.

When you think about how both bourbon and scotch are made, the processes are very similar. There are some big differences but you ferment the mash, you distill, then you age.

So why is bourbon so sweet?

It’s all about the corn mash. The stuff those geniuses ferment.

Bourbon’s mashbill is made of at least 51% corn, often far more (closer to 70% as an average). Four Roses has two mashbills, one with 60% corn and one with 75% corn. There are various high-rye, low-rye, wheat and whatever else mashbills but all share one characteristic – at least 51% corn.

Scotch, on the other hand, uses mostly or all barley in its mash and the glucose content of corn is much higher. That glucose is what gives bourbon its easily recognizable sweetness.

51%+ corn in the mash is why bourbon is so sweet.

11 thoughts on “Why is bourbon so sweet?

    • Sweetness simply cannot pass the distillation. The text is simply not right… The sweetness most be related to the cask or addition of caramel to adjust the color…

      • Bourbon isn’t allowed to have additives like caramel (by law). It’s likely because of the new charred barrels used for aging. When the wood gets charred, it caramelizes. Age the liquor in there for a couple years and you leech all of that out, which is, of course, the point.

        • Jens isn’t right. When distilling for bourbon it cant exceed 80% alcohol and when put into the barrel it can’t exceed 62.5% alcohol. Then what is the rest. corn has a high sugar amount which can translate into having a sweet bourbon and since wheated bourbons are sweet is because the wheat has less taste and uniqueness then rye or barely so it allows the natural sweetness to come out. you may still get some from the barrel but thats what happens.

          • Glucose and compounds with high boiling points will not boil off during distillation. The remainder of the distillate will be simply water boiled off. When you double or triple distill a solution you end up with a solution with higher and higher concentrations of alcohol. I hope this post isn’t taken as condescending or patronizing. I just wanted to offer my input to this post and I know this message doesn’t confer tone properly.

        • Incorrect. STRAIGHT bourbon is not allowed and coloring or flavoring, but blended bourbon is. That said, since the characteristic sweetness is present in straight bourbon and blended bourbon alike, it absolutely is not due to caramel flavoring or coloring. That is ridiculous

  1. Sugar will not evaporate during distillation (this is why maple syrup can be concentrated by boiling). So, that the sugar is extracted from the wood is a likely explanation.
    Dr. Eric

  2. ok interesting – I stumbled on this thread after wondering why the nikka coffey grain whisky i have in my hand tasted so sweet to me. didnt realize that it is mostly (95%) made from corn mash so now it makes sense… except one more question – should nikka coffey grain whisky then really be called a bourbon?

  3. How is it even possible that someone posing as an authority is so wrong on this topic?

    First, as was already stated here, sugars including glucose do not pass distillation. Therefore, a freshly distilled spirit is always free of sugars of any kind. Aromatic compounds that give the spirit “sweet nose” can pass, though, and since taste and smell are closely related, they can give the impression of sweetness even without sugar.

    More importantly, however, yeast that creates alcohol can only work with sugar, so even if the original grain is not very sweet, it must be “malted”, i.e. the starches of the grain must be enzymatically broken into simple sugars that can be metabolized by the yeast into alcohol(s). So every mash or wash is sweet, because yeast works only with sugar.

  4. Realize this is an old discussion, but the author is correct.

    In theory, distillation would separate elements the way posts above describe. In the case of alcohol distillation meant to achieve the highest ABV end product possible it would be true. (“Neutral grain spirits” such as Everclear brand). It’s possible to achieve 95% ABV and all flavors and aromas of the fermented substrate are completely eliminated.

    In practice, it’s not the case in the production of flavored alcohols (whiskeys, rums, brandies and original styles of gin).

    We need to begin with the understanding that the starting point is a mixture of alcohols and water. And although the process of distillation is meant to separate one from the other, it’s not possible to separate them entirely. In the case of whiskeys, rums, brandies and original styles of gin – it’s also absolutely undesirable.

    So with that starting point, there are two reasons why glucose or fructose or sucrose – if there is any in the fermented mixture at the time of distillation – indeed comes through into the distillate in whiskey or brandy production.

    The two reasons in short form:
    1 – Low ABV wash to start (i.e. very high percentage of water to alcohol);
    and
    2- inefficient distillation method/process.

    1 – Low ABV of the fermented wash itself
    Producers of whiskeys and brandies are concerned with creating a flavorful end product. These flavors are negatively impacted at higher ABV in the original fermented wash (distillers beer, whatever term you chose as long as we’re on the same page it doesn’t matter much for our discussion here).

    Negatively impacted in the sense that either: A) yeasts that can tolerate very high ABV may not produce the target flavors and aromas; and/or B) yeasts in a high ABV wash may produce “off” flavors – undesirable flavors either by nature of the alcohol-tolerant yeast strain or by a less tolerant yeast colony under stress (consider that alcohol is their waste product).

    Commercial distilleries may compromise by blending more flavorful product with neutral grain spirits. This would present as an inferior whiskey or brandy (or at the very least, not top shelf).

    For our discussion to have meaning, this lower ABV wash translates into the possibility that the fermentation is completed to the distiller’s satisfaction before all of the fermentable sugars are consumed by the yeast. The remaining sugars may not be detectable to the tongue at this stage, but can be measured using a hydrometer. (In truth nobody is measuring remaining sugars for the sake of sugars – they’re measuring to discover whether the fermentation has run its course,and to calculate the ABV of the wash or distillers beer.)

    2- Relatively inefficient distillation methods/process
    An accident of history in a way – traditional distillation methods use very simple equipment. This equipment was the way it was done for centuries. Called a “pot still” it’s truly nothing more than a pot for boiling liquid, with a tube to channel steam away and cool it so that the steam returns to liquid form. From the first drop of condensed distillate there is a relatively high percentage of H2O included – in the order of 20% would not be unusual. Not pure H2O – it also carries with it the other contents of the mixture.

    Traditional whiskey-making almost always includes two passes through the distillation process.

    The first, called the stripping run, is meant to collect as much alcohol and flavor as practically possible from the original fermented wash. The collected distillate from the stripping run may average 35% to 50% ABV and is going to contain undesirable higher alcohols as well as compounds that give one a hangover of biblical proportions. Roughly 70% of the original liquid remains in the boiler afterward. It still contains alcohol, and flavors, but it is as different from its original form as is the stripping run distillate.

    The second pass through the pot still is called the “Spirit run” and it’s this run that generally speaking creates a final distilled product suitable for aging or consumption.

    The spirit run begins with the newly collected distillate at about 40% (watered back to 40% if necessary). The undesirable higher alcohols evaporate and condense first, at lower temperatures. Here, too, the ABV would be well under 90%. Meaning that the balance is H2O bringing with it other components. As the spirit run progresses, the ABV of the distillate decreases (the amount of H20 + increases). The temperature of the steam increases due to the higher boiling point of the remaining mixture of alcohol and H20 in the pot, and it requires more energy to heat the mixture. Thus, the inefficient process becomes even less efficient, bringing through a greater and greater percentage of H2O and other elements.
    Generally speaking the middle third of the total distillate collected (called the “hearts”) is the majority portion of the final product, and the distiller adds to it some smaller amounts from the beginning third and the final third of the distillate. From those first and final thirds come significant characteristic flavors. And this is where the art of distillation and blending become evident. A master of the craft knows how to run the equipment and how to separate the good from the bad though the senses of taste, tough and smell. The portions of the distillate used to create the product ranged from a starting point near 70%-75% down to perhaps 40%. Collected distillate above and below those ABV are not used in the final product. Usually they are added to the next new spirit run in order to extract more of the good potable alcohols.

    All of this demonstrates, however, that the distillate collected during the spirit run which makes it into the final product is 25% to 60% H20 + other components such as glucose, fructose, sucrose, etc.

    This is why Bourbon straight out of the still (while it can’t yet be called bourbon) is relatively sweet compared to Scotch style whiskey. And Rum is naturally sweeter yet (being a creation of a fermented substrate of sugar cane – the by product of sugar production called molasses).

    Wood certainly adds potential sugars (trees make fructose, too) and toasted or charred wood contain caramelized sugars. The contributions of wood go far beyond sugars of course. But the sugars from wood are a greater contributor to any sweetness in Scotch compared to Bourbon because barley as a substrate for fermentation has less sugar than corn. Bourbon would also include other grains as a maximum by law total 49% of the recipe – and as the author states its typically less than 30% – meaning its mathematically probable that there would be a greater sugar content in the distillers beer.

    This is typed directly into the response form without proofreading – so I hope I have been able to provide useful information in a cogent manner. My apologies if I failed. I thought it better to try than to simply say, “Yeh-huh, sugar does so come through in the distillation!”

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