Yield vs Flavor: Why Fermenting to 8% Can Win

Use concentration-factor logic to set fermentation ABV based on product category: flavor-rich spirits versus neutral spirits.

Quick summary

Core principle

Let's talk a bit about proof, alcohol percentage. I remember having had a discussion once with a customer that said, like, wow, did I find an amazing yeast.

It can actually help me ferment my base wine to around 13%. So I said, like, OK, that sounds like a lot.

I mean, are you trying to make vodka? No, no, he was going to make a brandy.

He wanted that brandy to be flavorful, because he's a craft distiller. So I asked him, like, why are you so happy with 13%?

I said, well, it's an amazing find, and there's no yeast other than this one that can actually bring me or my wine up to those high proofs that I need to make my amazing brandy. And I said, I get the alcohol production side of it.

I mean, 13% is way more than, for example, which is a normal goal, right, in fermentation, around 8%. So your yield is going to be higher.

But again, on yield, on economies of scale, cost per liter, you're never going to out-compete big alcohol. And he said, but the yeast is also very good at flavors.

I said, maybe the yeast is, maybe the yeast isn't, but the procedure isn't. And craft distilling is about flavors first, getting the flavors right first, and only secondary about the alcohol creation process.

Flavors first, alcohol production second. What could be the advantage or disadvantage?

How it works in practice

For example that we create a wine, a base wine, with the same amount of esters. X liters of this, X liters of that, same amount of esters. Now we're going to distill it.

We're going to do whatever we want with it. But it ends up in a bottle, for example, at 40%. Now what's the concentration factor here?

So what is the expected ester concentration factor? Same amount of esters here as we had in this wine. Same amount of esters in the wine, but we only get 3 times the concentration.

5 to 3 basically means that this product has around 66% more flavor. And not in a sense that, I like it better, this and that, don't you love it? But in terms of ester count, we can put it through a CNG machine, and we can actually measure how many taste molecules are there.

So even if the yeast is very good at making certain flavors, and maybe it is, maybe it isn't, we'll have to test that. For sure, I'm wondering if it's going to bridge that gap to 66%. I think it will have a very hard time doing that.

What I want you to take away from this is actually quite simple. It's not about yield in alcohol, it's about yield in flavor. And there's a balance between the two.

It's not a positive balance, it's a negative balance. The higher proof you are, the less flavor concentration you'll get. The lower proof you are, the higher concentration you get to bring it to, for example, a 40% bottle.

Now, that's interesting, right? We have to ferment longer, it takes longer, lower proof. Because if we do 2% to 40, we get 20x, right?

Common mistakes and decisions

Well, the problem is that we have to do a lot, a lot of distillation in order to get from 2% to a bottle strength of finally 40%. In other words, it's a lot of money, a lot of work. There is a point when it's not worth it anymore.

8% is really the sweet spot. If you want to make flavor-rich products, 7.5%, 8% is perfect for a craft distiller. If you want to make vodka, hey, you're with me here, right?

If you want to make vodka, you want to have less flavor, go for a wine with a higher proof because it concentrates less into your vodka. Lower concentration factor means a lower concentration factor of the associated esters, of the associated flavor molecules. Ferment a high proof wine for a vodka.

Ferment a low proof wine for something that needs to be like a brandy, taste rich, a rum, a whiskey. We've got customers that intentionally go to 5.5%, 6% because they've listened to us when we had the iStill University course here at iStill headquarters. And maybe you can do it now because, well, I've told you, right?

But we have customers that search for those old varieties of barleys that aren't tuned for the biggest yield in terms of sugars because sugars relate to alcohol yield.

Continue with Contrasts flavor-first ABV logic with neutral-vodka priorities. to build directly on this foundation.

Key Takeaways