A buddy and me have been going round and round on attenuation. We have decided to ask smarter people out there in BeerLand.

Here is the question. If we create a recipe in beersmith, and it says estimated attenuation is 83%… however, our yeast strand specs says that the yeast will attenuate to 65-70%… does this mean that we will end up with under attenuated and overly sweet beer?


Do think so to early gives funky flav. What i do let it stand 5 days longer. Let the yeast settle out compleete before you rack your beers. A grav and sample taste as well

I’m pretty sure estimated attenuation in beersmith is based upon the yeast you enter with the recipe. Can’t imagine where else the number would come from. Beersmith is a great program and I rely heavily on it but like any other software it’s only as god as the date entered into it. It can’t increase the attenuation of yeast.

The short answer to your question is yes possibly… a lower attenuating yeast could potentially give you a sweeter finished beer.

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Yeast does have an “attenuation” connected to the vial… This assumes that the brewer isn’t aware of some small, yet significant things, that can allow it to go… lower… Watch the temps of your mash… I have the ability to do a step mash… Start low, then ramp up… I can’t tell the difference in the finished brew… but I can see I see how my hydrometer readings do go below 1.010…Is it more alcohol production? Perhaps… Understand I don’t do much really dark, full bodied brews… I could go on about methods and why… won’t do that… Just pay attention to whats happening… read some… then some more… record what you are doing… One really fun one to do… replicate your brew… try a bit different temps for the mash… Record all you do… Sneezles61

thanks all… I have a Spike brewing unitank with pretty good control over my mash temp… electric heater and glycol chiller…

how do you step up the temp? what is your method?

I’ll start my mash at 142* a half hour later, ramp up to 156*… I have a meter that tells me what percentage of power is being supplied to my element… so when I reach my mash temps… I shut down to 12% power… Then when it time to boil, I put it to 100%… once I reach my boil, in my area, thats at 209, I can turn my power down to 55% to maintain a boil… Sneezles61

A stepped mash is not necessary for good attenuation. To put it simply a lower mash temperature around 148-150 will give you more fermentable wort where a higher mash termp 154-156 will give you less fermentable wort. Having said that you’re only talking about a couple of points difference on your gravity reading but a good palate will be able to tell the difference in the body of the beer.

I have done step mashes on my last two brews and both times yeast has exceeded attenuation specs, but not by any significant amount.

Sure. I didn’t say step mashes don’t produce better more fermentable wort. They can but you can get perfectly good attenuation from a simple infusion mash.

I save and repitch slurry for many generations and have found that 2nd, 3rd and 4th gen yeast tend to outperform first gen yeast as well but that doesn’t mean everyone should save and repitch slurry.

I agree. Just noting my recent experience. Single infusion works just fine. Almost all of my brews have been done that way.

This is a tricky subject and why it is hard to replicate recipes. If your going to get 87% attenuation from your yeast and you want a dry beer mash in the 150 range. If you want a maltier taste you should mash closer to 160 so that your final gravity would be higher. Or you could use a lesser attenuating yeast. What yeast are you talking about. The attenuation listed on the yeast is an average. I don’t know if beer smith tracks your brews and can predict the yeast attenuation I put mine in manually but in order to get it exactly the same all the time you would have to be super consistent.