A split batch experiment... the impact of yeast in beer.

Do you want to see how yeast impacts the favor of beer?  Take the simplest recipe of a beer, split it into two fermenting containers and pitch a different yeast in each.  In a few weeks, you can bottle the beer and try it.  Or, if that is too much trouble then relax, I've done the work for you.

A few weeks back we talked about the Munich Malt and Spaltz hops simple recipe beer.  Read the background here and then come back.  

This was a solid 5 gallon batch, and my largest carboy is 5 gallons, which doesn't allow for much headroom.  Plus, I wanted to do something different, so I split the batch, pouring 2.5 gallons into two 3 gallon carboys.  In one carboy, a dry packet of US-05 yeast was pitched and in the other Wyeast Kolsch yeast with a 800ml starter was pitches.

In the end, there is a distinct difference in the flavor of the beer, which we can get into in a bit.  Both finished at 1.010 (with the US-05 maybe pushing more toward 1.011).  Both have about the same color at the end.

The process was interesting too, as the Wyeast carboy began fermenting, much quicker, while the dry yeast took longer to get to active fermentation.  The photos below do a nice job of illustrating this.

After pitching.  US-05 on the left, Kolsch on the Right

After about 10 hours.  Activity on the right.

Day 2, about 36 hours.

Day 3, about 60 hours, activity on the left now.  Right is beginning to settle down somewhat.

Day 7, gravity check and color comparison.

Gravity on day 7, 1.012  (This was the Kolsch.)

Kolsch FG - Day 19.

US-05 FG, Day 19

Flavor?  The US-05 American Yeast is a cleaner yeast, which gives the beer a little sharper mouthfeel, and "cleaner" taste.  The hop bitterness is right there, along with the malt background.  A nice clean simple beer.

The Kolsch yeast yielded a higher ester profile.  The beer is more round on the mouthfeel, more fruity notes come through.  At bottling time the yeast character come through, which should subside someone.  Being a low floculating yeast, there is more still in suspension.  With time in the bottle, and additional chill time, the yeast will continue to drop out, clearing up the beer more.  Even in the two photos above, you can see that the Kolsch is more cloudy.  

Note also the activity level of the yeast.  The liquid yeast with starter was much more ready to go to work than the dry pitched yeast.  There were probably more cells in the dry packet, but I didn't bother to re-hydrate them.  I bet that would have made a difference too.  It's funny, because everyone will say to re-hydrate the dry yeast.  The packet itself says to pitch directly to the wort.  Go figure.

Now the questions remains, which will taste better?  Or is there a true definition of better in this sense?  They simply are different.

With the underlying style aiming for an Altbier, the Kolsch yeast will give that character more than the US-05.  The true malt and hops character will shine more with the cleaner US-05 yeast.  Hmm.  This seems to have been a good experiment.

Cheers!

Barley, Water, Hops, and Yeast - Part 4

"God is good!"  they exclaimed after tasting the beer, obviously a gift from above.  A few simple ingredients, a few weeks and Hokus Pokus, something amazing.  The water wasn't safe to drink, but this beverage was both safe, tasty, and nutritious.  Like liquid bread.  It made you feel good too!  Praise be to (name your favorite deity)!

Some will say the discovery of beer is a key element in the transition of the human race from hunter-gatherers to a more agrarian lifestyle.  This led to cities, and opportunity for education and learning, etc.  A monumental shift in the human civilization, and it is all because of the discovery of this wonderful substance we call beer.

How did it begin?  No one is quite sure, but it is believed to have been accidentally discovered.  It could have gone something like this.

A Story

Some 10,000 year ago an unknown ancient Sumerian forgot to bring his basket full of barley into the hut (tent, cave, hole in the ground?) one evening after another long day of travel.  It happened to storm that night.  Imagine his mood the next day while having to carry this now very heavy and water soaked package during the journeys of that day.  He probably had a hard time keeping up with everyone else, and I bet they made fun of him due to his lack of conscientiousness the previous evening.  Doesn't everyone know the importance of keeping the grain dry?

On and on they walked that day, and he became most thankful the next stop that evening was a scheduled three day stay.  He pushed through the day, knowing if he worked hard, he'd have time to relax upon arrival.  Later that night when they finally arrived, sore and tired, he was eager to drop the load off his back.  He immediately went in the hut/tent/cave, laid down and was fast asleep.

More rain ensued that night.  The next few days were uneventful, until the day of departure.  That morning, everyone was bustling around and gathered their cargo for the next journey.  Our friend too, went to gather his bundle of grain to find it setting in the basket, which was by now also full of water.  What is that lovely smell?  This water seems different.  Ever curious (and a bit thirsty) our hero decided to drink up.  "It's amazing!  Hey Maris, check this out," he exclaimed and called to his friend.  Soon the entire camp was gathered around this basket, full of this mysterious concoction.  It caused quite a stir.  What magic has happened in your basket?  We must stay here longer and more closely examine the evidence.

Yeast

Of course today, we know the source of that magic.  It is a single celled living organism known as yeast.  Or should we say billions of single cell organism.

Active Fermentation, the yeast krausen at the top.

There are a lot of yeast strains which have been cultivated and used for certain types of beer over the years.  Many breweries will have their own house yeast and will take care to preserve and keep it healthy.  Each type will impart a different set of flavors.  The yeast alone can have a huge impact on the flavor of beer.

We are fortunate today to have access to many various strains of yeast, including historic strains from all over the globe, through companies like Wyeast and White Labs.  With a little effort and know how, yeast from certain bottle conditioned beers can be cultivated and then used for brewing the next batch of beer.

For beer, there are two main types of yeast used.

Saccharomyces cerevisiae - Ale yeast, or "top fermenting"
Saccharomyces Pastorianus - Lager yeast, or "bottom fermenting"

The ale yeast will perform best at higher temperatures, between 60-74 degrees, and the lager yeast works best at temperatures in the 40-55 degree range.

Cultivated yeast, settled in hibernation at the bottom of the jar.

The possibilities and combinations of ingredients in beer really are quite endless.  I've only scratched on the surface here with yeast, but if I go on any longer, I risk you losing interest.  There are a lot of resources out there, including books specifically about yeast.  What is important here is the variety available to brewers and the fact that such a small thing has an enormous impact on beer.  In fact, without the yeast, there is no beer.

Yeast is good.  Yeast is good indeed.

Relevant Links:
Part 1, Barley

Part 2, Water

Part 3: Hops

Infographic of the week

This simple illustration is perfect for making a yeast starter. I ran across this somewhere this week.

Six easy steps.

Reuse your yeast through washing and harvesting

Washing and harvesting yeast can be a good way to save a little money.  Also, the amounts left over while using this technique will assure a high level of yeast for pitching into the next batch.

Here is the Dunerbrew quick how-to.

1. Obtain 6 pint sizes Ball jars.

2. Boil the jars in a large pot for 10-15 minutes, along with the caps.

3. Remove from the boiling water, with the bottles filled to the top with the boiled water, and cap loosely.  This will result with 6 sterilized bottles filled with sterilized water.

4. Close the caps tight while the water is still rather warm.  When cooled completely the cap will be sucked in, creating an air tight environment.

5. Let these set for a day at least, to obtain room temperatures with the water.

6. Rack the beer off of primary fermentation, leaving the yeast layer, along with the trub and hop residue setting at the bottom.  The yeast in the carboy will be clean, as the alcohol in the beer will not have permitted any bad things to remain alive.

7. Open and pour the water from 4 of the jars into the carboy, keeping careful to keep the caps and jars sanitized during the process.

8. Swirl the yeast and trub in the carboy, creating a solution with the newly added water.
Carefully fill each of the 4 jars with the contents of the carboy, and cap.

9. After an hour of so, the contents in the jar will begin to settle, forming a layered effect, with the trub and hop residue falling first to the bottom.  The white solution is the yeast still suspended in the water.

10. After the trub has settled, open the other two jars (one at a time) and dump the water from them.

11. Carefully open two of the jars with the yeast and pour the two into the one empty jar, keeping careful to pour out the suspended yeast only and keep the trub in the original jar.  The yeast from the two jars should sufficiently fill the one jar.



13. Do the same with the other two jars, into the remaining empty jar.

14. You will now have two jars full of yeast.  Let them set overnight on the counter, which will result with any remaining trub settling again to the bottom first (there should be very little if done properly in the prior step).  The yeast will slowly settle too.

15. Place in the refrigerator, where the yeast will fully settle to the bottom and go gently into a state of dormancy.

 

The photo to the left was taken after a few days after refrigeration.  You can see the dormant yeast as the whie layer at the bottom.  It will last like this for several months (though in reality it will be used in a couple of weeks), until it is time to use in a Starter, for preparation for brewing the next batch.

 The process for washing and reusing yeast has been illustrated previously on this blog, via a couple of How-To videos.  This is how I learned to do it.  That post can be found here.


Hey, do you like brewing and craft beer?  Be sure to "Like" the Dunerbrew Facebook Page. 

Cheers!

Another Yeast Harvesting Video

For whatever reason, I'm fascinated with washing and harvesting yeast for reuse.  Perhaps this is only because yeast can be the the most expensive component to all-grain brewing.  It is, however, a fun project and I feel a little like a farmer when harvesting yeast.



The key component for me (which saves a lot of worry) is to keep everything sanitized.  Boil all the water and keep a spray bottle of Starsan on hand... and spray down everything.  ...my two cents.

Cheers!

All you have to do is shake it for 45 seconds.

Oxygen is the enemy of beer, except at the very beginning, to help the yeast get off to a rocking start.  Whether the instructions say to "rock the baby" or simply to aerate, I've historically just guessed as to how to accomplish this without thinking much more about it.  I'm not about to invest in an oxygen tank!  So what do I do?  I shake the carboy a few times, trying to get a good froth going.  I pitch the yeast and then shake some more.  Simple enough right? 

What do the experts say?  Here is Greg from Wyeast.


My take away is this.  15ppm = shake for 45 seconds.  Easy enough.  This is also perhaps another reason to leave some head space in the carboy...better splashing while aerating.

Washing and Harvesting Yeast

After the last post about Yeast Starters, I wanted to look into harvesting yeast again.  I did this only once so far, but it can be a good way to save money by maximizing the yeast you do purchase.  All it takes is a little bit of knowledge, planning, minimal equipment (mason jars, a kitchen) and time.

The internet can be a good resource.  The links below will say it better than I can.  The first, I found quickly and gives a good overview of the process.



This video is the one I studied prior to doing this myself, and found it very beneficial, from Beer Geek Nation.



I fully intend to harvest the yeast from my next brew and continue to use it.  With proper planning (maintaining sanitation) I can reuse the yeast again and again, ultimately creating my own "House Yeast".

Fear not.  Try it!