Brew UK Forum | General Brewing Discussions
Yeast Attenuation
Morning all,
I'm trying to understand the way the different yeasts work and also set up the correct attenuations in my brewing software. My last 2 brews using US-05 have both dropped out a much lower FG after fermentation. I have no issue with this as it's giving me a really crisp, dry finish but obviously wanted to get this set in my software so I can control alcohol content and flavour on my next brews.
First brew my OG was 1052 and target FG was 1013 (I hit 1006). Second brew OG was 1041 and target FG was 1010 (I hit 1005). Some basic maths thrown at it gave me a rough attenuation of 85%. Does this seem too high to anyone or have I calculated it correctly?
I can't bare to end up with another 6% beer.
Once I understand this I'm going to move to mash PH and then full water treatment (not straight away though).
Thanks guys,
J.
Responses
Posted 1 year ago by Moderator
There was a topic on how to calculate attenuation here - http://www.brewuk.co.uk/forum/topic/attenuation#post-8148
and here is the formula - [(OG-FG)/(OG-1)] x 100
If its gonna ferment lower then you can just adjust the amount of malt used. Most yeasts have attenuation slapped on the lable somewhere and programs like beersmith will lets you put in the og and fg, from there you can adjust the amount of grain required.
Plannin'-
Loads a beer after an upgrade!
nathbrew@gmail.com
Posted 1 year ago by Member
Some manufacturers give attenuation figures but Fermentis just give us High, Medium and Low. Here's their guide:
Tips and Tricks
Fermenting:
Condtioning:
Drinking: Twibute Clone, PJ Clone
Posted 1 year ago by Admin
James, just adjust the software to give you a final reading nearer to what you are achieving then adjust the recipe accordingly. Obviously so long as you are US05.
Posted 1 year ago by Moderator
Hi James. Take a look here.
http://www.wyeastlab.com/hb_yeaststrain.cfm
There is a huge amount to know about yeast and Wyeast is a great place to start. They give you all the information you are likely to need about all their yeast strains. It's also important to remember that when they test their yeast and calculate attenuation, it's done under ideal conditions, and you are unlikely to get the exact same result. What their guide does is gives you a good idea of what to expect from a brew using any of their strains of yeast. I know it seems expensive, but you can easily propogate the yeast to supply you with yeast for months from 1 sachet. My 1968 strain has been propogated so many times I calculate it now costs about 60p a brew. I can soon tell you how if you are interested.
The problem with packets of dried yeast is that they are unpredictable, and usually ferment far further than the beer should be, leaving no residual sweetness.
Planning: - To get some more brews on now the weather's a bit cooler
Fermenting: - Ginger Beer experiment
Conditioning: - A normal bitter with Styrians
Drinking: - All of it!!
E-mail: arnyfris@gmail.com
Posted 1 year ago by Member
I've still got heaps to learn and starting with yeast seemed to make sense. I'd love to know how to propagate my yeast at some point, not sure if i'd always do it but the knowledge is great to have.
I plan to move to wyeast packs at some point but sticking to dried for now.
Posted 1 year ago by Moderator
Hi James. You're absolutely right. There's loads to learn, but don't overcomplicate the issue. The more you know the more you are likely to start worrying yourself. The Wyeast site gives a good understanding of yeast for brewers, and that's all you need.
I use Wyeast and propogate it. All you do is get 2 x 4 pint (or 2 lt) milk containers. Thoroughly clean and sterilise them. Mix up 220 gms of DME with 2 lts of boiled water. Let it cool to room temperature (about 22°c) and leave the yeast pack alongside it so they are both at the same temperature. Slap the yeast pack to break the nutrient bag aand wait for the bag to swell. Then add the yeast to your 2 lts of DME solution, shake it very thoroughly to aereate it and immediately divide it between your 2 containers with 1 lt in each. Leave the tops loose to let the CO2 escape or the bottles will explode with the expansion. Over 2 or 3 days the yeast grows, giving you enough to pitch into the wort in 1 container, while you keep the other container in the fridge to do it all over again for yout next brew. Do it 5 times and the cost is down to pennies.
Planning: - To get some more brews on now the weather's a bit cooler
Fermenting: - Ginger Beer experiment
Conditioning: - A normal bitter with Styrians
Drinking: - All of it!!
E-mail: arnyfris@gmail.com
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