Can type of yeast affect alcohol percentage?

[HughRichardson]

I have been experimenting with liquid maltose in conjunction with Coopers kits.

In the first test case I used a Coopers English Bitter kit with 26 litres water plus 1.8 Kg Maltose and Safale S-04 yeast to get a FG of 1.014 and an estimated 4% alcohol which is just about right. I normally brew these English Bitter kits with a couple of extra litres of water as that helps to moderate the rather excessive taste of the end product.

In the second case I used a Coopers Real Ale Kit with 23 litres water plus 2.2 Kg of Maltose and the Coopers supplied yeast. Based on the lower water volume and larger amount of fermentable sugar (maltose) I was expecting that to work out stronger, but FG remained at 1.03 for almost a week and was clearly not going any lower. Alcohol probably around 3.3%, although I was shooting for 4.5% or even 5%

Temperatures in both cases were maintained fairly evenly at 21 to 22 degrees C.

My question therefore is could the Coopers yeast have been solely responsible for the lower alcohol in the second case? Would a second sachet of yeast have made a difference (added at what stage?) or should I use a yeast enhancer of some kind – or stick to the Safale yeast?
The Real Ale has not yet conditioned enough to taste, but the English Bitter brewed with the maltose tastes very much better than that particular product usually does, so I am happy with the basic ingredients - but need to juggle the quantities and yeasts until I have something repeatable.

 

[el_caro]

Different yeast will result in slightly differing FG based on the same amount of fermentable material.

However I believe the 1.030 FG is way too high for the Real Ale kit and wonder about the hydrometer readings.

I would be concerned about bottle bombs developing at FG 1.030.

 

[hercher]

The short answer is yes, the type of yeast you use can affect alcohol levels. Different strains of yeast attenuate differently. The higher the expected attenuation, the higher the alcohol.

That said, there are a number of other variables, as well. As both of your batches were extract, with maltose added, you should have had pretty fermentable worts. But if you start adding a lot of crystal malt to your recipe, you add unfermentable sugars in to your batch.

In your case, another question might be how old those kits were. Dry yeast has a pretty long shelf life, but if that was an old packet of yeast, if might not perform as well.

A second sachet of yeast probably would have helped your second batch. Add it at the beginning of fermentation for best results, though you can add it later if you feel it necessary.

 

[HughRichardson]

Thanks for your input, El Caro, and I agree that 1.03 sounds too high – but I think the FG is probably correct. I got a reading of 1.03 after 8 days in the fermenter, and I left it there for a further week, thinking like you, that the reading was too high. However during that week, I got the same reading after two days, four days and again when bottling three days later.

I thought I was hearing bubbling in the air lock, during that period, but at very long intervals, so I think that the fermentation was really all done. If I had added a second sachet of Coopers yeast after a week in the fermenter, do you think that could have led to further fermentation? Or would two sachets pitched at the start be worth a try?

Bottle bombs probably not an issue as I use plastic 1.5 litre PET bottles and after 2 days in secondary conditioning, the bottles are not yet fully hard. (Actually I even used extra priming sugar in the hope it might raise the alcohol level a bit – I table-spoon per bottle instead of 1.5 teaspoon)

 

[HughRichardson]

Thanks for useful input, Hercher
I am not too sure what crystal malt is, so cannot answer to that. The Maltose is in the form of a honey-like thick viscous liquid. The beer kit can has gone out in the trash, but I have one last can (English Bitter) bought at the same time, and it has an expiry date of 27 April 2014. The guy I buy the kits from keeps them refrigerated until he sells them, and on delivery, my practice is to remove the yeast sachets and keep those in the fridge till needed, while the cans of kit just sit around at room temp!

Is it possible that this particular maltose may respond better to Safale Yeast than the Coopers variety? - Or is that plain old nonsensical??

I am going to brew up that last can of Bitter soon but I have no more Safale Yeast so would need to use the supplies yeast again – maybe I will go with two sachets. Might that affect the end taste or are quantities too small for that?

 

[el_caro]

I think Hercher has correctly raised the point that the coopers kit yeast may have been of suspect viability and that may have resulted in them not finishing the job.
I do not think the fermentables would have been an issue for healthy yeast of any variety.
Adding more than the recommended amount of priming to raise the ABV is not a good idea as it can lead to over carbonation of the bottles.

If the yeast pack you have is healthy then generally it will suffice to brew a 23L Coopers kit. I would recommend rehydrating the yeast prior to pitching.
Pitching too much healthy yeast can impact on the quality of the beer just as underpitching does. I doubt however that 2 packs would be enough to cause a problem in that regard.

 

[kontrol]

Is it possible that this particular maltose may respond better to Safale Yeast than the Coopers variety? - Or is that plain old nonsensical??

Maltose is a simple sugar (It's two glucose units). It shouldn't be a problem for yeast.

If you had added maltotriose the answer would have been yes. Different yeast handle maltotriose differently. Some are better at handling maltotriose than others. Maltotriose is 3 glucose units.

On why it got stuck with with your second brew here's some food for though.

1. Like other have said, the yeast viability might be a good suspect.

2. Aeration is very important for yeast to reproduce and attenuate your beer correctly. If insufficient oxygen was provided it is possible that your beer didn't attenuate correctly, specially if the yeast wasn't very healthy. Maybe your second brew wasn't oxygenated correctly.

3. Your temperature of fermentation looks fine. However the temperature that you pitch your yeast is also important. If the temperature was too high or too low you can impact the performance of your yeast.

 

[HughRichardson]

Thanks Kontrol
I think my pitching temperature was fairly good on both batches, although I have thrown out that part of the records. The Real ale was at 24 C if memory serves. I recall it took about a day to bring it back down to 21 C afterwards.

It sounds more and more like I may have used an expired yeast pack.

You clearly have some extensive knowledge of these matters - is there a lot of difference between Maltose and Malt Extract from the brewing perspective?

 

[kontrol]

Maltose is the principal sugar in the wort when mashing. Malt extract is a made of glucose, maltose, maltotriose and higher saccharide.

Yeast needs glucose in the fermentation during the lag time IIRC, you couldn't make a 100% maltose beer without an impact on the fermentation.

Maltose also need 1 more step to be completely converted. Yeast breaks down the maltose into glucoses and then process the glucoses. I have no idea if this has a huge impact on the speed of fermentation.

That's what I know, I'm just thinking out loud. I don't know if it would impact the flavor of the beer much. As far as I know 100% maltose is used when baking.

 

[HughRichardson]

That is certainly most informative. From your remark that:

Yeast needs glucose in the fermentation during the lag time IIRC, you couldn't make a 100% maltose beer without an impact on the fermentation.​

I would gather that I have probably been messing up by using just Maltose. In some brews I have also added half a kilo of clover honey, and (more by good luck than good management I must confess) I added 0.87 Kg of liquid Glucose to the 1.5 Kg of Maltose in the brew of Coopers English Bitter that I put in the fermenter yesterday!!

I was lucky to have a sample on hand and bunged it in because there was on 1.5 Kg in my Maltose jar left and I figured it might need a bit more sugar.

For future reference, do you think that Maltose plus half a Kg of honey would do as well as the glucose - the latter being a little hard to obtain on a regular basis?

I really appreciate your obvious depth of knowledge on this topic, and hope other readers will also benefit from the discussion!

 

[kontrol]

Your can of Coopers already contains the Glucose required. It's dry malt extract.

You seems to be adding a lot of plain sugar in your brew, is there a reason? You shouldn't add more than 5%-10% of plain sugar (Glucose, sucrose etc..) in your wort. If you want to boost the flavor and ABV you should add liquid malt extract or dry malt extract when boiling the wort.

 

[HughRichardson]

That is good to know!
From what you say, I ought to be OK with around 2 Kg of liquid maltose plus a can of Coopers beer mix for the future?

Since getting away from white granulated sugar, the only sugars I add normally are liquid maltose and sometimes some honey. In the latest brew, I just happened to have a couple of sample jars of liquid glucose taking up fridge space, and decided to use them instead of the honey. I believe that honey is 100% fermentable and can add a slight sweet note to the end product. However I think any taste is not apparent below 500 grams of honey. Actually when I bought the maltose, I thought it was the same thing as malt extract - you live and learn I guess! Still it has produced good tasting beer so far and is quite easy on the pocket.

 

[hercher]

Quite honestly, Hugh, I wouldn't add anything to your kits. They are intended to make a good beer as is.

If you want to experiment or make stronger beers, may I suggest you design your own by purchasing some dry and/or liquid malt extract, some grains for steeping, hops, and yeast. You may wind up spending a little more, but you get a beer that is distinctively yours. I also think you'll find brewing to be a little more fun when it is a beer you designed.

 

[HughRichardson]

Hercher,
Actually the Coopers kits do require the addition of fermentable sugars in order to generate the alcohol. The instructions say that you can add a Kg of white sugar - or replace that with other fermentable sugars to taste - or words to that effect. While plain white sugar does work, I have found Maltose, DME or Dextrose in varying proportions does improve the end product. The Coopers kits are more or less the only ones available in SE Asia except by special arrangements, so a certain amount of creative tinkering is common. I cannot imagine where I would obtain the ingredients to brew from scratch - finding the maltose supplier was something of a coup!!

 

[kontrol]

The Coopers can are DME. Instead of adding sugar, just use two can. You will get a maltier, tastier product. Adding sugar thin the body of the beer and with sucrose in too high quantity you can get off flavors.

What is the kind of ingredients that you can access where you live? Where did you get your cooper can?

 

[HughRichardson]

Thanks
I'll try that !

 

[HughRichardson]

Well, as they say – “the proof of the pudding is in the eating” – and for sure the proof of the brew is in the drinking thereof!

I always bottle a few ½ litre bottles for sneak preview sampling – I guess I know my own patience – and I just cracked one of the samplers of the Real Ale brew. Gravity readings, fermentations, sugars etc aside – it tasted FANTASTIC!! Actually one of the best I ever made, and not really all that weak tasting either (good head and head retention, lovely colour and clear as crystal)– and that was after 8 days in the bottle.

Real Ale will definitely form a major component of my next order. But lessons learned – I will probably stick to rehydrating the yeast in future. Thanks to all for many good tips and guidance.