How precise must one be in brewing?
 

When brewing my stout I came across a number of issues.

1. My target mash temp was suppose to be 150 for an hour.

What happened is I couldn't get it passed 145 (despite using the strike water the sparge calc told me) so I started adding in hotter water a quart of a time but never got it to the target. Thus I ended up mashing it at 145 for 1.5 hours.

2. Boil time is 60 min

My timer broke. So now I'm estimating and could be off 10-15 mins.

Thanks

prolly not a big deal. mashing at 145 is fine for most beers. better then mashing 2 high i guess. you will be fine as long as you pitched your yeast in a chilled wort and everything was clean and sanitized.

145 is fairly low for a mash temperature... You might start running into some mash efficiency issues that low. Don't know your batch size, but it takes quite a bit of hot water to raise the temp. Try preheating by rinsing your mash tun w/ boiling water before adding grain & strike water, that should help you hit your mash temp (sometimes those calcs don't account for the MLT being at room temp). If you don't want to do that, you may have to add 2-3 degrees to make up for the heat loss to the mash tun.

As for the boil time, your IBUs may be off a bit but other than that I'd say you should be okay as long as everything you used to transfer to the fermenter was sanitized!

It will turn out fine. Perhaps a little thinner bodied and more alcoholic than expected but a stout nonetheless. At least you went 90 minutes with that lower temp mash because it probably needed it.

Usually there's no problem boiling a little longer than needed. I would err on the side of a little too long, but off by 10-15 minutes either way is not a big deal.

The sum of the equation is that you're going to end up with beer! :D

Depends on your goals.

If you're trying to clone a specific beer or get maximum efficiency you need to be very/incredibly precise.
If you're just trying to get an alcoholic beverage made from grain you can be incredibly imprecise.

The likely impacts of how you brewed your stout are that:
The final gravity will end up pretty low. This is due to both the low temperature mash and the long time. Your stout will likely finish dry as well, which many people like.
The longer boil time will affect hop utilization and in more isomerism of the flavor compounds resulting in higher IBUs than the recipe originally was designed around.

In summary if this was supposed to be a clone it will (probably) be easy to tell them apart, but by no means will it taste bad. I recently made a batch where the the mash temperature varied wildly, I had 147 all the way up to 160. I just bottled it and it was a good beer. I just won't be able to create it ever again.
Remember people have been making beer for thousands of years, and for many of them having absolutely no clue what was going on. to paraphrase Dr. Ian Malcom in Jurassic Park " Beer finds a way"
RDWHAHB

The making of "a" beer is not a precise subject.

Creating, Reproducing or Repeating a recipe (a process) used to make a specific beer is, out of necessity, precise.

You made beer! I try to hit the numbers the best I can, but it rarely happens. I end up making great beer people like, but my consistency sucks.
To be consistent you need your numbers to be bang on, your environment to be identical etc. I have made similar beers back to back etc but there's always been a slight difference. This is what makes me enjoy homebrew. As a beer lover my palette never gets bored.

If you have a decent palette, and tasted the same recipe someone made with the proper mash temp , you would notice a difference, but they would still be great beers. I concur with above, if your equipt was clean, and the yeast was pitched correctly and you are storing the beer correctly, game on!

Probably not, especially if he mashed for 1.5 hours. However, he will have more beta amylase resulting in a thinner-bodied beer and lower FG than had he mashed at 150F.

thanks a bunch! I hope its not so thin bodied that it taste flat.

If your MLT is 10 gallons add about 5 gallons of 180+ degree water for 10-20 minutes to preheat your container. Ever since I started preheating I have always been within 1-2 degrees of my mashing temps after letting the temps rise about 10 minutes and giving the mash a good stir for those 10 minutes.