weirdboy

Recipes 

Grain bill also plays a big part. If you have 30% crystal malts in your grain bill, you are not going to get much attenuation.

Assuming the same grain bill and healthy pitching rates, a higher mash temp will have the biggest impact on attenuation IMO.

Some higher-flocculating yeast strains (like S-04) don't attenuate as well normally because they drop out pretty quickly and form a tight clump on the bottom of the fermenter. If you manually agitate the yeast cake a bit, though, you can get somewhat higher attenuation out of them.

Bithead

Recipes 

After I switched to AG I was having a problem with too low FG. I started doing a mash out and have had no problem since. Seems like conversion was continuing while first and second runnings were sitting in the BK before actually starting boiling. I was also doing double batch sparge.

iambeer

Recipes 

I'm confused. I thought that a higher temp in the mash and sparge means more sugars from the grain. But this thread seems to indicate that the lower the temp, the more 'fermentable' sugar? What am I missing?

atom

Recipes 

you have it backwards... lower mash temp will produce more fermentable wort than a higher temp mash.

iambeer

Recipes 

Cool, thanks for the answer.. but why do I read that sparging with hotter water is to rinse sugars from the grain?

Jayhem

Recipes 

So what is the solution? Should I start my boil with the first runnings while I'm sparging into a second container and then add the second runnings to the brew kettle once I'm done sparging?

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atom

Recipes 

typically during the sparge you are just "rinsing", the conversion is done during the mash (with lower temps).

pjj2ba

Recipes 

This is correct. Whether the water needs to be hot or not is debated. Probably the biggest advantage of a hot sparge is that hot liquids simply flow faster. The sugars are already dissolved so, as far as that aspect is concerned , tempeature make no difference. The sparge is simply moving the sugars away from the spent grain. Cold water will also "wash" the sugars off the spent grain.

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Yooper

Recipes 

I do a mash out first (I tend to fly sparge), and I do start the first runnings on the heat as the sparge finishes. This holds the fermentability profile of the wort, if that makes sense.

But you don't have to use a second container, unless you are gravity draining and the kettle is too high- you just drain your runnings into the brewpot.

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iambeer

Recipes 

Thanks. This is starting to make a lot more sense now.