from the President
By Chris White
The trade press has been full of stories this year
about the poor barley crop. The Milwaukee Business Journal, for
instance, reported earlier this year that the crop was the smallest in
more than 65 years, driving up costs for brewers.
The barley crop creates more urgent problems for
brewers besides rising costs, however. The barley crop itself was poor,
which has led to malt with higher protein, more beta glucan and other
complex carbohydrates, which creates fermentation difficulties. Malting
companies expect this to continue for another three to six months, until
the new crop works its way to brewers.
Many brewers have already experienced and worked
though problems, but some may have not had trouble yet. Your not out of
the woods yet, however, because you may have more trouble when making
high gravity beers for the holidays, which have a higher amount of malt.
Even when the malt quality is good, trouble with certain batches can be
apparent when brewing high gravity beers.
First off, you may have noticed that the fermentation
takes longer to reach full attenuation. The telltale signs are normal
fermentation for the first few days, but the fermentation hits a wall
and stops 2-4 Plato higher than expected. The yeast is normal and
vitality is high, but the complex sugars facing the yeast can be more
than they can metabolize.
If given a few extra days, sometimes the yeast can
work its way through the complex sugars and reach full attenuation with
no further effort on the brewer’s part. The best corrective action for
the brewer is to work the sugar profile in the mash. Try lowering the
temperature of the mash. Record the best temperature, as this may be the
one you will want to use for the next six months. Enzymes can be added
to the mash, particularly if doing a high gravity beer. Alpha-amylase
enzymes would be most beneficial. If you experience run-off problems,
beta-glucanase enzymes can be used.
On the fermentation side, there are several things
you can do. Over-pitching your yeast can help by having more cells to
attack the abundance of complex sugars. Raising the fermentation
temperature once 5 Plato is reached can also help. If the fermentation
is stuck, you can employ a strategy used by wine makers, who commonly
experience stuck fermentations, due to the high alcohol involved and the
low nutrient value of wine. Wine makers will commonly pull yeast from
the bottom and restart it in a small quantity of aerated, fresh must.
They let this go for 12 to 24 hours before adding back to the
It is important to have the yeast active, because it
is always difficult to get yeast to ferment in a beer or wine that is
already fermenting, because of the alcohol present and the lack of
oxygen. So if you add more yeast, regardless if it is from the
fermentation or new yeast from our lab, do so only after getting the
Also, consider using yeast nutrients if you do not
already do so. Servomyces can help because zinc deficiency will add to
the problem of slow/stuck fermentations. If the yeast is healthy, it is
better able to cope with fermentation stress. If you have any other
questions, I would be happy to provide you with further advise. Just
write me at email@example.com.
Chris White is President of White Labs Inc. and is a chemistry and
biochemistry lecturer at the University of California, San Diego. He has
a Ph.D in biochemistry.