Yeast Comparison: S-04 and S-05 - Side by side.

Yes - it's more about yeasty goodness!

This time, we're doing a true side by side test of Fermentis' S-04 English Ale Yeast and their S-05 American Ale Yeast.

I've been brewing for a touch over a year now and have completed around forty or so brews successfully. They have included a wide range of English and European ales and ciders and some other experimental and speciality beers.

The character of how each yeast behaves in the fermenter, its influence on how fast or slow the ferment is, whether it's a top fermenting yeast or a bottom fermenting yeast, how fast it flocculates out and many other characteristics is very individual. Using the right ingredients with the wrong yeast can render a batch to be like ordinary homebrew made by a novice. I've used some very ordinary ones that came with the cans of goo when I was starting and I've used some delicious exotic White Labs vials that have made for some very surprising successes from some really crap ingredients.

Obviously, one of the first few things you can change when you're getting started is the yeast. That's why I'm taking a closer look at S-04 and S-05 and sharing the results with you.

Here's where you can find the data sheets on each type:

S-04: http://www.fermentis.com/FO/pdf/HB/EN/Safale_S-04_HB.pdf

S-05: http://www.fermentis.com/FO/pdf/HB/EN/Safale_US-05_HB.pdf


>From my point of view, S-04 tends to be typical of an English Ale yeast. Fairly quick ferment, reasonably temperature tolerant (up to 24C according to the pack), willing and ready to make good ales, porters and stouts. As and English style yeast, it tends to accentuate the malt flavours and tends to be a medium to high flocculator, leaving a rather clean and clear product even at the end of primary fermentation.

S-05 is a bit different. As with a lot of global perception of all things American, this is definitely a bold and brassy yeast. It tends to favour the hops moreso than the malt, giving a sharper, cleaner finish to the taste and making the flavouring and aroma hops more pronounced. Sadly, it's not a big floccer so it leaves the beer rather cloudy by comparison to S-04. However, there are clarifying techniques that we can talk about another time to overcome this issue - the simplest of which I will tell you now: time. Leave it sit a few weeks or a couple of months and it will be reasonably clear, excellent tasting and better mellowed.


The yeast can be pitched either by rehydrating it into a cream or sprinkling the dry yeast onto the top of the wort. Either method is rather easy and in my experience equally effective.


So - on to the testing!


So that the comparison is completely fair, the wort and fermentation needed to happen at the same time so that every part of the process would be exactly equal. The style of ale had to be something reasonably 'normal' so that there were no additional complexities which would interfere with the yeast being compared fairly.

Here's the recipe for the wort:

400 g Cracked Carapils steeped @ 70C for 30 minutes
7.9 kg Liquid Light Malt Extract
30 g Pilgrim Hops (10.8% AA) @ 60 minutes
25 g Fuggles Hops (6.1% AA) @ 30 minutes
25 g Fuggles Hops (6.1% AA) @ 15 minutes
... made up to 50 litres.

This gives: OG = 1049, IBU = 34.3, EBC (est.) 14.9, IBU/SG = 0.719.

In plain English, that means an ale that will finish up around 5% alcohol, with a pleasant balance of bitterness and sweetness but leaning slightly toward the sweeter end of the spectrum.

The wort was made in one big batch, cooled to 20C, stirred to homogenise it, divided equally between two fermenters and topped off to 25 litres in each fermenter.

Yeast was pitched, one sachet of each yeast type into each fermenter. Rather than just allowing it to find its way into the wort, it was stirred in aggressively in order to introduce as much oxygen into the wort as possible.

Fermentation was four days at 22C.

FG = 1011.


Here is a pic of the beer drawn off from the fermenter prior to bottling:

Don't you love my high-tech laboratory glassware? :)

As you will notice, the beer on the left is very cloudy indeed. That's the S-05 yeast. The one on the right is S-04.

While this pic might cause you to leap to conclusions about which one you would choose, take a moment to ponder out a few more points:

• The nature of the S-05 tends to create a hoppier, more lively tasting beer which more of the market is accustomed to. It tends to have a slight bite to it. Even at this stage out of the fermenter without bottle conditioning, it's certainly the spicier of the two.
  
• S-04 tends to flocculate out faster and produce a cleaner beer sooner. However, as I've mentioned earlier in this article, it does tend to be more malt driven so you should take this into account and increase your first hopping accordingly to gain more bitterness and let the malt drive the flavour and aroma.
  
• As you notice, the two beers both have quite different colour profiles. The S-04 is a good copper colour and the S-05 is a brighter amber colour. I'm not one to care much about colour but about taste, especially in these beers at the lighter end of the spectrum.

So - what yeast to choose?

That depends on personal taste and your intended "grain to brain" schedule.  

S-04 If speed is your thing and you're OK with a young beer, then I would choose S-04 and a hops schedule to suit. The above hops schedule does not suit. If anything I would increase the first hops either by weight alone or by both weight and boil duration, depending on your taste. I prefer an ESB with an initial hoppy bite, mild aroma and let the sweetness be a lingering afterthought.

As far as speed goes, a fermentation around 18 - 22C would last around four days and after five days of secondary fermentation / bottle conditioning, you're pretty much good to go. Flocculation continues in the bottle and results in a rather bright and clear beer that only improves with time, out to about two months. If you keg, then this is the one to go for. Clean and clear in a hurry.


S-05 If you can spare a month for a rather good, modern style beer that is reminiscent of some of the west coast USA craft brews then S-05 is your yeast. It will take a couple of weeks at least for the yeast to drop out of suspension. Drinking too early while the yeast is still suspended tends to lead to bottom-ripping farts and runny poo. You have been warned.

Again, the fermentation time and temperature is much the same as S-04, but longer secondary fermentation / bottle conditioning will really reap rewards.


In both cases, if you allow a day or two in the fridge prior to drinking you will find the result much better than if you rapidly chill the beer in the freezer for an hour or so and then keep it in the fridge. The technical aspects of this have been explained to me, but I don't recall those in detail. Suffice to say, it works. Try it.


This article is already far too long and probably boring to anyone who isn't a beer nerd, so I will put the pics and tasting notes into another post in a few days.

Take care and happy brewing.


Cheers!!


EDIT (09/12/09): No pics of the finished product, sorry. Drank it. Yummy. :)

Let's talk about yeast.

For a blog that's all about yeasty goodness, there hasn't been a whole lot of talk about yeast.

So, let's talk about yeast.

Baking yeast is interesting enough, but I can't say that I'm very deep into it at the moment so let's talk about brewer's yeast.

Beer making is simple enough at first glance. It's water, hops, malt and yeast. What does yeast do?

Simply, it makes carbon dioxide and ethanol as two of its important by-products. The carbon dioxide is what gives us the bubbles in our beer and the ethanol is the alcoholic goodness which we all know and love. There are other by-products but they're beyond the scope of this post.

In brewing, yeast goes through a couple of major stages. The first stage is where is consumes as much of the oxygen present in the wort so that it can reproduce. When the oxygen runs out, the yeast commences producing alcohol.

There are literally thousands of yeasts from many suppliers that are used in hand made beer and commercial beer alike. Some for the hobbyist are close copies of famous commercial yeasts used in your favourite off the shelf beer. Some are the real yeast used by your favourite brewery.

There are two main groups of yeasts:

• Dry
• Liquid.

Dry yeasts are made by a spray drying process, among others. Basically a solution of live yeast is made at the factory, which is then sprayed as fine droplets and dried by a variety of processes. The dried yeast is then coated in a nutrient or other material to ensure freshness and then packed into individual sealed foil pouches.

Liquid yeast on the other hand is the liquid from which the dried yeast is made. "What's the difference?" you ask.

The difference is that the dry yeast is more stable over a longer period of storage and can tolerate a reasonable amount of mishandling and still produce a good result. Ideally, if they are kept in the fridge and then warmed up to room temperature a few hours before use you will have a good result.

Liquid yeasts need to be temperature controlled (cool) in order to keep the yeast alive and have a shorter 'use by date' of about six months from when they leave the factory. These liquid yeasts come in a variety of packaging, but the most common is the plastic screw-top vial, much like this one:

Similarly, liquid yeasts need to be warmed to room temperature before use. Check the manufacturer's instructions on the pack.

The other difference is price. A packet of dry yeast is about $4 - $5. A vial of liquid yeast is about $15 - 18. Worth it? I say yes.


If you buy kit beer, it usually comes with a package of yeast under the lid. For all intents and purposes, it's OK but it won't give you the best beery result for a variety of reasons. If the kit is from a reputable maker such as Coopers (http://www.coopers.com.au/homebrew) or Morgans (http://www.morgansbrewing.com.au/products.asp?range=Overview), chances are that the yeast which it came with is pretty good, but through non-optimal handling it may not be in the best condition to give you a top grade result. They're good yeasts and able to withstand the kind of abuse someone new to brewing can dish out, purely through not knowing enough. In the hands of an experienced brewer they can be used to produce a rather pleasant every-day beer.

You've put your money on the table, bought your kit and bits or taken that next step to all-malt extract brewing and want to make your result shine. After all, by this stage you're after quality and not just a buzz. The buzz is a nice side effect.

That's where after-market yeasts come into play.

The most common stepping stone from the original kit yeast is to one of the Fermentis dry packet yeasts. A couple of the most popular are S-04 and S-05.

S-04 is styled after an English ale yeast. It produces a lovely result with some residual sweetness, much like a real English Ale such as a Best Bitter or a Special Bitter and the like. It tends to enhance the malt aspects of the flavour profile. It's really easy to use and very reliable and economical. I'll tell you something to make it even more economical a little later in this article.

S-05 is an American style yeast, producing a result that is more dry and tends to make the hops a little brighter and more forward in the flavour profile. Great for making something like the famous Anchor Steam Beer and similar.

Dry packet yeasts are very easy to use and rather predictable in how they do what they do. You can either just sprinkle them into the wort and let them do their thing or you can rehydrate and feed them a little to get the action started a little sooner.

Naturally enough, Fermentis has a massive range of yeasts which are suited to a very diverse range of applications and therefore flavour profiles, fermentation characteristics and more. We can get more into what kind of yeast does what in another article.

If you want to go a little further in quality, then it's liquid yeast time for you. I'm certainly not going to go through the White Labs or Wyeast list with you one by one - I'm just going to mention a couple which I have used and found interesting and that give a great result.

My new favourite for making English ales is WLP002 English Ale Yeast. There are some others for making English ales from White Labs which have slightly different characters. However, WLP002 is a good starting point. It's an aggressively flocculating yeast. This means that it clings together and drops out of solution very quickly when it has nothing to do, or starts to feel lazy. To get around this, you need to give the fermenter a rock just to get it off the bottom and keep it doing its good work. The end result is a beer that looks rather clear, almost like commercial filtered product and has a truly traditional flavour.

Another one which caught my eye and I used for my 'Froehlichen Kirschenbier' (Cheery Cherry beer) is WLP550 Belgian Ale Yeast. I had been buying various Belgian beers at local shops at up to $9 for a 300 to 330 ml bottle - far too expensive to enjoy a few every evening. This yeast was the solution to that problem and wow did it deliver! It's a rather highly attenuating yeast. In other words, if you start out with a high specific gravity it will finish with a low specific gravity. It takes about ten days to ferment at around 18C, but it's certainly worth it. I hear that a little extra heat towards the end of the fermentation, say 22C, helps bring out some of that Belgian funky character to make a truly distinguished and authentic drop. Highly recommended.

One of the other gents I know who brews is a huge fan of Nottingham Ale Yeast (available as WLP039 from White Labs) . He tells me that it's a very fast fermenting and aggressive yeast. Some yeasts politely stay in the fermenter and do their work. Notto goes mad and works hot, up to four or five degrees celcius above ambient temperature. If you're into ESB then this is the beastie you need.

Take a look around the Fermentis site (http://www.fermentis.com) and White Labs site (http://www.whitelabs.com) for more information and to see their outstanding ranges of yeast.


Here's the hot tip I promised earlier: How to make yeast costs lower.

• Choose a yeast and ferment as usual.
• Bottle or keg as usual, leaving the yeast cake in the bottom of the fermenter.
• Collect a cup of yeast in a sanitised container.
• Add around 300 ml of water at around 27C and about 10 - 20 grams of sugar (I prefer dextrose, but others are OK)
• Stir well with a sanitised spoon.
• Cover with cling wrap.
• Prepare your next wort, clean your fermenter.
• Wort into the fermenter, dilute to volume.
• Measure OG.
• Add the yeast which you've collected, fed and watered.
• Stir powerfully to get as much air into the wort as possible.
• Ferment as normal.

You can do this about five or six times before the yeast ceases to be viable or begins to cause problems.
There are more advanced yeast farming techniques but I won't go into those at this time. This is the quickest, easiest, least expensive and least equipment intensive method to get more value for your yeast money.

Happy Brewing!