Higher Mash Temp = Lower ABV?

[pdog44450]

I am planning on making a "Blonde Ale" type beer tomorrow. I have all my grains and input them into BeerSmith 2 and have been fine-tuning the recipe today to get everything in check. The default mash temp was input at 150F while the recipe calls for a 154F mash, albeit I cut the recipe in half, I wouldn't anticipate that making a difference as it is scaled. At a 150F mash, it says the final product will have a 5.1% ABV, while at a 154F mash it will be only 4.7% ABV. Is there a reason there is such a difference or is it just BS's error? It isn't a HUGE difference but it is enough to make me wonder about it.

 

[LLBeanJ]

The higher the mash temp, the lower the amount of FERMENTABLE sugars are converted, which means a higher FG and lower ABV than you would see if you mashed at a lower temp.

 

[thekraken]

As I understand it mashing at different temperatures puts different enzymes to work. The higher the temperature then the less fermentable the sugars are that are converted from the starches. Less fermentable meaning less sugar the yeast will be able to eat and convert to alcohol. It's not a beersmith error.

 

[bbrim]

That looks pretty close based on my experience. I tend to run 150 for my Blonde, I like that one crisp while keeping the IBUs down. GL with the brew!

 

[pdog44450]

The higher the mash temp, the lower the amount of FERMENTABLE sugars are converted, which means a higher FG and lower ABV than you would see if you mashed at a lower temp.

As I understand it mashing at different temperatures puts different enzymes to work. The higher the temperature then the less fermentable the sugars are that are converted from the starches. Less fermentable meaning less sugar the yeast will be able to eat and convert to alcohol. It's not a beersmith error.

Appreciate it gentleman, I completely understand how it works now.

 

[pdog44450]

That looks pretty close based on my experience. I tend to run 150 for my Blonde, I like that one crisp while keeping the IBUs down. GL with the brew!

Thanks! What do you usually shoot for IBU wise? I'm at 24 right now but based on what I've read with blondes, the hops don't come through too much. Just curious what you normally do

 

[bbrim]

I usually target 21-22 IBUs with about 1.5 oz Saaz at 5 minutes. My FG is usually 1.010 or 1.011 with ABV of 4.2.