Most Brewers yeast work on sucrose first, breaking it down into its glucose and fructose componets. They then consume the glucose first, followed by fructose, maltose and finally maltotriose. Of course being that they are live little beasties, they can sometimes behave differently.
Most yeast strains are glucophilic, utilizing most of the glucose in the wort before consuming the other monosaccharides. They also ferment most of the monosaccharides before fermenting maltose and subsequently maltotriose. In fact, it is known that high levels of glucose and fructose in a wort (e.g. >15–20%) will inhibit the fermentation of maltose. This repressive behavior is probably a common cause of stuck fermentations in worts containing a lot of refined sugars — the yeast have fermented the monosaccharides and then quit, leaving more than half of the total sugars unfermented.
Types of Sugar
Brewing with Fruit
When selecting a fruit to add to your brew it is a good idea to keep some things in mind. Knowing what the fruit will add in flavor, color, sugar content and pH will help you in deciding amounts of the fruit and other ingredients to add with it.
Most fruit contain between 10 and 15 percent sugar when ripe. Most fruits contain a mixture of fructose, glucose and sucrose in their sugar makeup.
One misconception of brewing with fruit is the need to properly deal with pectin and pectin haze that can come with brewing with fruit. Pectin is carboxymethylcellulose and is helpful when making jams and jellies as it aids in thickening. The pectins are extracted most often when the fruit is heated. Thus, if you brew without heating the fruit as we suggest, then issues with pectin haze should be minimized. Also, the most common fruits used in brewing are naturally low in pectin to start out with, minimizing this concern further.
A word of caution: not all parts of all fruits are edible and thus those parts should not be added to a brew. What does this mean? The pits of some fruits contain cyanogens which break down to release hydrogen cyanide. It is highly unlikely that you will produce enough cyanide in your brew to cause cyanide poisoning, however, simply removing the pits prior to fermentation is always recommended.
(The chart below is a work in progress. We strive to continue to add information when we find it. This said, some of the areas may be left blank where I have yet to find the information. The fruit with the sugar section left blank is an example of this.)
6 thoughts on “Sugars (and brewing with fruit)”
I’m planning on making a mojito mead and I’m unsure on how much line to use to prevent it from being to acidic. The plan is to brew 5 gallons with:
12 lbs raw Texas honey
3 lbs molasses
1 cup fresh squeezed lime
6 oz. Bruised mint leaf
1 cup white sugar
Sounds pretty good to me! Should be alright. If you’re worried, try half the lime juice in primary and half in conditioning?
I was reading the list of fruits and was wondering, the most used fruit for fermentation I belive is apple, but I cant find it on the list 🙂
Any specific reason why its missing?
Martin Aka Babaleo Babaneo
That is a good question. I was planning on adding to the list, but I too am surprised that apple wasn’t included in the original listing I found through research. Look for further additions as I continue my research.
I bet Lychee is wrong; it lists it at 1.5 but I bet that should be around 15: lychees are incredibly sweet. Grape-like sweet. And indeed it’s used a lot to make wine in Asia.
Come to think of it, they’re actually in season here in Thailand; I’d love to try making lychee wine and then avoid making it hideously sweet like most producers do over here. Just that making wine from fresh fruit scares me a little; need to get the juice out, then make sure it doesn’t spoil so it’ll involve chemicals..
Thank you for bringing this to my attention. It seems that Lychee varies drastically on their sugar amounts based on the different cultivars. I have amended the chart to show the range as best as I could find. As far as making fruit wines from fresh fruit, we do it all the time and have no need to add chemicals. Tannins and Acids aid in preserving wine and are often found naturally in most fruit. You may find our videos on brewing with fruit on our You Tube channel, CS Brews to be rather helpful if you haven’t watched them already.