So yesterday we brew our second beer. As expected, some errors occured during the process, which is alright, we're learning! :)

So the main problem is that we were only able to keep the mash temperature at 60-62°C (140-143.5F). It lasted 60 minutes.

When taking OG, we were around 1.052 instead of around 1.062.

I wanted to know if:

1- Is it what affected OG? (I guess yes!)

2- What are the other effects that might happen?


1 Answer 1


You are almost right; the mash gravity depends on the mash efficiency which in turn depends on the mash temperature and mash time. A higher mash temperature will result in longer sugars which are harder for the yeast to ferment. This leads to more full bodied beer. A lower mash temperature will give shorter sugars which are easy for the yeast to ferment, leaving a lighter body.

The process of getting sugars from the grains to the wort is called starch conversion. The starch in malted barley is converted at around 60-70 degrees Celsius, as can bee seen from this chart.


  1. Yes, that is probably it. Mashing at 60C is a bit low
  2. Your beer will have a lighter body.
  3. As a lower OG means less sugars in your beer giving the yeast less to feast on, the alcohol content will be lower.
  4. Boiling with lower gravity increases your hop utilization, giving you more value for your hops!

Also, the OG-estimate that most brewing software calculates for you is based on your so called mash efficiency. You have to find you own efficiency before these estimates get reliable.

Good luck with future brews!

  • Great answer, thanks! I will read further about that mash efficiency, because following the link you provided, when trying to calculate my "ppg", I get around 18 for this batch, and around 20 for the first one. But on the first one, we pretty much reached the expected OG, so I thought that after calculations we would be closer than that to the 30 ppg! Oct 28, 2013 at 19:56
  • Alright, so I was uing imperial gallons. I used this site to calculate and we got a 63.69% efficiency and a ppg of 22,5. Thanks again! Oct 28, 2013 at 20:16
  • 4
    Mash gravity doesn't directly depend upon mash temperature - it's more closely tied to efficiency. Sure, temperature does affect efficiency to a degree with respect to how long it takes the mash to complete. With the lower temp, the mash should have been longer and an iodine test for complete conversion should have been done to be sure of completion, otherwise let it go for 120 minutes. Pilsners are often fermented in this region to give a super-fermentable wort, but need long mash times - 3 hours in some cases.
    – mdma
    Oct 28, 2013 at 20:46
  • 1
    If it is highly fermentable, does this mean that the FG will be lower than expected? So it would give a beer will less sugar, alcohol close to where it should have been? Oct 29, 2013 at 2:20
  • 1
    Correct - less residual sugars and higher alcohol.
    – mdma
    Oct 29, 2013 at 11:50

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