Ester boost through glucose addition?

[Miraculix]

I've just been reading the following article and under the section describing the wort carbohydrate composition, it is stated that glucose metabolism of yeast results in more esters than the metabolism of other sugars.

https://onlinelibrary.wiley.com/doi/full/10.1002/jib.145

I know that, for example in English styles, invert sugar, which is essentially almost 50% glucose plays a big role as an addition to the wort, for flavour reasons (and for bringing the fg down).

In German brewing there is a specific way to boost glucose content in Hefeweizen wort (was it called Hermann Verfahren?), in order to boost ester production.

Wouldn't it make sense to add pure glucose to the wort to boost ester production, where esters are wanted?

Do you guys have any additional sources of information regarding this topic?

Cheers!

 

[JimRausch]

Interesting article. I skimmed it, but will save it to study in greater detail. I did see the line that indicated increased ester production when fermenting primarily glucose, and lower esters with maltose. I guess based on this one article, which does seem well referenced, it would make sense to add more glucose if you want more esters. Maybe those Belgians and English knew something.
I'm pretty sure you know Miraculix, but for the sake of others who might not, glucose=dextrose=corn sugar.
And another interesting point I saw, especially to go along with the recent Brulosophy exbeeriment about using glucose vs, sucrose, this article indicted that there is a noticeable difference in fermentation of the two in ester and higher alcohols production.

 

[Miraculix]

Interesting article. I skimmed it, but will save it to study in greater detail. I did see the line that indicated increased ester production when fermenting primarily glucose, and lower esters with maltose. I guess based on this one article, which does seem well referenced, it would make sense to add more glucose if you want more esters. Maybe those Belgians and English knew something.
I'm pretty sure you know Miraculix, but for the sake of others who might not, glucose=dextrose=corn sugar.
And another interesting point I saw, especially to go along with the recent Brulosophy exbeeriment about using glucose vs, sucrose, this article indicted that there is a noticeable difference in fermentation of the two in ester and higher alcohols production.

I assume you are refering to this one? http://brulosophy.com/2019/02/25/sugar-additions-dextrose-vs-sucrose-exbeeriment-results/

Interesting read! Although they are not clarifying what the difference in taste of the final beers specifically is.

I had a thought about invert sugar. Invert sugar is basically made by splitting a sucrose molekule into a glucose and a fructose molecule. The longer it is heated the more side reactions and caramelisation happens, which contributes to flavour, but generally speaking the big majority of the sugars in invert sugar is glucose (or dextrose, however one wants to call it) and fructose. Give or take a few percent, I guess it would be somewhere around 50% fructose and about 50% glucose regarding the sugar content in invert syrup.

In the paper I linked to, it is written that fructose doesn't contribute to the enhanced ester production. This makes me wonder, if it would make sense to create something like a fake incert syrup, that only consists of glucose and caramellized glucose. Basically dissolving glucose in a bit of water and heating it up till it starts to darken (caramellize) up until the desired degree.

This wouold mean that the ester boosting ability of the sirup must be twice as big as the ability of normal invert syrup so either more flavour or half of the amount of syrup required.

I think I will give it a try with my next ale.

 

[ESBrewer]

Yes, interesting concept and it may play some role in taste of beers where plain glucose or invert is added. Thanks for posting.

My limited experience says that adding pure glucose mainly makes beer thinner and sometimes watery (lacking malt flavors). But maybe also more estery? Then the question is how much esters do you actually want and what type of esters are produced (no bananas into my bitters, please). We know that most of the time brewers want to restrict esters by keeping the temp relatively low. This is also what the paper above says. In my (summer time) experience, estery strains can go way overboard by simply increasing the temperature.

I think standard invert should work in this context because in normal wort, amount of glucose is limited (wort being rich in maltose) so that absolute & relative amount of glucose would rise considerably even if there is some (neutral?) fructose in the mix. Of course glucose is expected to be more effective and has been used widely in brewing beer (mainly in non-inverted form).

If you heat pure glucose, it may not reach as interesting taste as typical invert syrups. Those are usually made using impure raw sugars (demerara etc.) and the impurities are thought to Be important in the development of taste of the syrup.

 

[Miraculix]

Yes, interesting concept and it may play some role in taste of beers where plain glucose or invert is added. Thanks for posting.

My limited experience says that adding pure glucose mainly makes beer thinner and sometimes watery (lacking malt flavors). But maybe also more estery? Then the question is how much esters do you actually want and what type of esters are produced (no bananas into my bitters, please). We know that most of the time brewers want to restrict esters by keeping the temp relatively low. This is also what the paper above says. In my (summer time) experience, estery strains can go way overboard by simply increasing the temperature.

I think standard invert should work in this context because in normal wort, amount of glucose is limited (wort being rich in maltose) so that absolute & relative amount of glucose would rise considerably even if there is some (neutral?) fructose in the mix. Of course glucose is expected to be more effective and has been used widely in brewing beer (mainly in non-inverted form).

If you heat pure glucose, it may not reach as interesting taste as typical invert syrups. Those are usually made using impure raw sugars (demerara etc.) and the impurities are thought to Be important in the development of taste of the syrup.

I see..... Damera etc. is actually nothing but sucrose plus added molasses in varying percentages. There are recipes available for making your own brown sugar with sucrose and molasses. Maybe by adding a bit molasses to glucose, this effect could be simulated?

Regarding esters, i am actually particularly thinking about Weissbier esters and the Imperial Yeast Pub (the fullers strain), which is already a flavourfull thing, but I simply cannot get enough of this taste. Would like a supercharged version of it!

 

[ESBrewer]

Try Pub at 22-23C with some yeast nutrient. I think you will get quite a lot of esters that way. At least Fuller's bottle yeast did not produce too much off flavors but the estery character was even too prominent to me..

 

[mediant]

I know that, for example in English styles, invert sugar, which is essentially almost 50% glucose plays a big role as an addition to the wort, for flavour reasons (and for bringing the fg down).

AFAIK another reason for using sugar/corn/etc adjuncts is to dilute FAN levels, which may get too high in HG all-malt worts or with specific barley varieties.

Do you guys have any additional sources of information regarding this topic?

Yup, see this for instance - Yeast: the soul of beer’s aroma—a review of flavour-active esters and higher alcohols produced by the brewing yeast, which references several other works on this topic.

If you're in the mood to try adding something, then check out this - Aroma-active ester profile of ale beer produced under different fermentation and nutritional conditions
Here they studied effects of adding zinc and l-leucine. I really consider ordering some l-leucine food supplement to make a trial batch. OTOH, every trial I made with Maltaseverfahren resulted in an ester bomb, so simple temperature control may just be enough for homebrewing...

 

[ESBrewer]

AFAIK another reason for using sugar/corn/etc adjuncts is to dilute FAN levels, which may get too high in HG all-malt worts or with specific barley varieties.

And the FAN levels are especially high in some high protein malts, but modern British malts tend to be rather low in FAN. So glucose might have been useful to dilute amino acids in old times in British brewing but not so much these days (and the use of sugar has apparently decreased in popularity). The adverse effects of FANs include some off flavors.

 

[bierhaus15]

Interesting how the paper reiterated that high maltose decrease esters, as is commonly used in high gravity brewing. Besides that, I know higher glucose wort levels corresponds with elevated S02 production (especially in lagers) and is among the least stable wort sugar for beer oxidation.

 

[ESBrewer]

A commercial example of glucose + Fuller's yeast is their ESB 1980 replica version which is found in stores here at the moment. I didn't like it very much, it has the yeast character quite similar to modern non-glucose version (maybe the nature is a bit altered though?), but the body and overall taste is more watery. The esters were more prominent and body was fuller when the modern grain bill was fermented at (too) high temp in my experiment.

 

[ebbelwoi]

I think it was mentioned in this article:
http://braumagazin.de/article/brewing-bavarian-weissbier-all-you-ever-wanted-to-know/
http://braumagazin.de/article/stilportrait-weissbier-von-nelken-und-bananen/

Whoops, mash is finished, gotta run...

 

[Miraculix]

I think it was mentioned in this article:
http://braumagazin.de/article/brewing-bavarian-weissbier-all-you-ever-wanted-to-know/
http://braumagazin.de/article/stilportrait-weissbier-von-nelken-und-bananen/

Whoops, mash is finished, gotta run...

Yes, that's also the first article I read about this subject. Really good one for Hefeweizen, if not the best source of knowledge online for this style.