Beer Forum

Longest title for a topic I've seen in a while.

Anyway I thought I would pass on a tip I just learned. Had lunch the other day with Tyson Arp, lead brewer for Nebraska Brewing Company. This topic came up and he had some interesting stuff to say.

He had been working for some time to shorten the time to reach final gravity for his Belgo-American IPA (Hop God). He always seemed to hit a plateau a few degrees higher than his target final gravity. It would always take an extra week or so to drop the last couple of points. To deal with this he started playing around with the timing of the sugar addition.

On big beers everyone around here will tell you to add the sugar during fermentation rather than the boil so you don't cause osmotic shock to the yeast due to the high O.G. The question arises of exactly when during fermentation. I have seen answers ranging from when fermentation is complete (then restarting fermentation with sugar addition) to just after high krausen.

Tyson played around with all of these and kept careful records of the gravity drop over time. He had developed a theory that the metabolism of the yeast changes due to the type of sugars it has been eating. When the type of sugar changes, the metabolism has to go through some changes so it can adapt to the change in diet. This will sometimes cause the fermentation to stall until the change is complete (if it restarts at all).

His experiments showed that the best time to add additional sugar to the fermenting wort is at or very shortly before high krausen when the yeast is most active and can more easily adapt metabolism. Once he started doing this he virtually eliminated that plateau at the end of fermentation, cut almost a week off the time in the fermenter and allowed him to hit his target F.G. everytime. Very important for a commercial brewer with limited fermenter space.

For those of us who brew big beers using sugar to boost the gravity, I think this will help us avoid the stuck fermentation problem. Myself I have been adding sugar too late in the process (at about 50% attenuation) and have been hitting that plateau. Sometimes the beer sits in the keg for months slowly dropping in gravity before getting where it needs to be. I generally age those beers for a year anyway, but it would be nice to get them to drinkable earlier.

Just thought I would pass this bit on.

Wayne

Yeah, that was a very interesting conversation! It still seems very counterintuitive to me but Tyson has data so...

Maybe Jamil and Chris White's new book will speak to this in some way.

It makes sense.

There is a post in another thread about whether to include the sugar in your OG for determining how big a pitch to make when adding the sugar during fermentation. If you use the bigger OG, you'll have more yeast but the sugars won't be there yet. I suspect the yeast wouldn't multiply enough times to consume the later sugar addition.

By adding the sugar before peak occurs, the yeast are still multiplying and should grow enough cells to consume the additional sugars.

For a typical big Belgian beer of 8-11% I've always thought this was a solution looking for a problem.

I've not had any problem with these fermenting in under a week when adding sugar to the kettle (temp control, adequate healthy yeast, ramping).

Note I don't believe in "under pitching" Belgians based on Belgian practice. All top cropping breweries pitch less yeast than propagating breweries. Since I propagate Belgian yeast, I pitch that rate.

I don't venture into the realm of 13%+ beer (probably never will) and will admit that some heroic measures may be necessary there.

Quin wrote:It makes sense.

There is a post in another thread about whether to include the sugar in your OG for determining how big a pitch to make when adding the sugar during fermentation. If you use the bigger OG, you'll have more yeast but the sugars won't be there yet. I suspect the yeast wouldn't multiply enough times to consume the later sugar addition.

By adding the sugar before peak occurs, the yeast are still multiplying and should grow enough cells to consume the additional sugars.

AFAIK simple sugars are extremely easy for yeast to process and if you're adding the sugar late you're not increasing the sugar content past your OG anyways so there shouldn't be much of a need for the yeast to reproduce to carry out the fermentation of the simple sugars that were added. I used to be more into winemaking a couple years ago and I never saw any information about calculating pitching rates when making a batch of wine. The little 5 gram sachets of wine yeast simply say that 5 grams of yeast is sufficient for up to 6 gallons of must. I'm fairly certain this is because wine must is all simple sugar (fructose, sucrose, etc.) which is much easier for yeast to ferment and therefore less dependent on the pitching rate for healthy fermentation.

My theory right now is that when Tyson adds the sugar at the first sign of fermentation, he has made the yeast to do the majority of it's growth in an all-malt wort which makes the yeast configure it's enzymes for maltose and larger sugars. Now when the yeast see simple sugar they go ahead and ferment it alongside the complex sugars rather than fermenting the simple stuff first which helps the fermentation procede quickly with no need to re-ramp up activity to process a large dose of sugar later in the process.

I don't know, it's just a theory.

On big beers everyone around here will tell you to add the sugar during fermentation rather than the boil so you don't cause osmotic shock to the yeast due to the high O.G

Didn't know this... I thought it was due to the yeast metabolizing simple sugar first, and then stalling on sugars produced by the mash... Maybe thats what osmotic shock is. A simpleton such as I will have to google it

This is good stuff!

Hmm this is interesting, I have a beer that I am planning on brewing in two weeks that has simple sugars in it, I will have to give this a try.

If adding the sugars pre-high krausen, then wouldn't the yeast tend to devour the more simple sugars before consuming the maltose in the wort? It seems like this could lead to incomplete fermentation, but I guess the studies might show differently. I would love to see some data and have it repeated by others.