When's the best time to Bump Up?

[andy-10]

I know every recipe will be different, but, in general, how long do you wait before adding more malt or sugar?

I tend to make high alcohol beers, which are very active at first, then quieten down to a gentler fermentation after a week. I usually bump up then, when the brew is less dense but when there are still plenty of active yeast cells.

 

[Dutto]

I don't add anything after pitching the yeast, but with high SG brews I start the fermentation off at the lower end of the temperature range for the yeast so that it has a nice slow start ...

... and use a "Blow-Off" system rather than an air-lock just in case the brew decides to leave the FV!

 

[Zephyr259]

Don't do this either but with wine and mead, where it's slightly more common, I think you mostly just wait for the very active initial fermentation to calm down. Why do you step feed beer, how high abv are we talking?

 

[Ghillie]

Why not add the DME/sugar at the end of the boil?

 

[andy-10]

The highest I've reached is 12%, but more typically 9%. As for step feeding, I believe that overloading the yeast with too much sugar at the beginning stresses it, killing a lot of it off.

The point about a lower temperature to start with is definitely true. I noticed that when I started doing this the brew both smelled and eventually tasted a lot nicer. Apparently, too much heat in the early stages of yeast growth can produce a lot of off-flavours, and smells. A lot of those flavours are later broken down, but not all of them.

 

[Zephyr259]

What kind of yeast are you using? Building a bigger starter, or using multiple packs of dry yeast, for a high gravity fermentation is standard practice and with good aeration the yeast should handle it fine.

 

[BeerCat]

I have only ever heard of step feeding wine. I follow your advice with high Abv beers, triple pitch and plenty of oxygen.
Amylase when pitching will also up the Abv. Try gluco300 the brut IPA enzyme.

 

[andy-10]

I use Gervin High Alcohol mainly, but experiment with others too. Good point about the starter. I suppose I could keep one running at a cooler temperature for a couple of days before pitching. I'm trying to keep costs down, so I don't want to be buying a lot of packets of yeast.

Yes, I use Ritchies Amylase. That helps. I whisk in plenty of oxygen, initially and on bump ups, using a cordless drill fitted with a cafetiere plunger. Gives a lovely froth.

 

[foxbat]

Why not add the DME/sugar at the end of the boil?

The brewing-lore is that if you add simple sugars like dextrose then the yeast will consume those first before they start on the disaccharides like maltose (i.e. your wort) and may stall early giving you a stuck fermentation. Hence you often see people waiting until primary fermentation is slowing before adding sugars directly to the fermenter.

My own experience is that a healthy correctly sized pitch of yeast will go through the whole lot no problem at all and I add dextrose 10 mins from the end of the boil to sterilise it.

 

[Zephyr259]

Yeah, plenty of sugar in a lot of Belgian styles and they don't struggle.

I'm not sure if be introducing a lot of air when adding more sugar to an active fermentation. I'd probably try to keep it to a minimum by that stage. Could be wrong though.