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I started brewing with the grainfather about a year ago and have done 5+ brews. I have been milling my own grain from the start. All of the brews have had a problem with astringency: some more some less. So in my last brew I changed a number of parameters:

  • I got the grain pre-ground from the shop to rule out that I was milling too fine
  • I did not wait until the very last drop of the sparge but removed the grain basket which there was a little dropping still going on. I let the basket drip into a bucket after this and around 1 litre of fluid was in there
  • I set the temp of the boil to 98degC as I live at 500m+ (had nothing to do with astringency was just a coincidence)

The grind looked good, there was a bit of flour and all grain were cracked or split. The sparge went noticeably better and quicker than with my own grind but it was still a healthy 40min. The boil was not very vigorous: it was not hopping like a volcano but there was a very good circulation going on.

It was this https://byo.com/article/neipa-style-profile/ recipe but changed a bit - I went with 5kg of pale ale malt - My boil was 60min - I did a hop stand but just added the hops at 0min and left to stand for 30 mins

I did not measure the pre-boil gravity or the volume. I think the volume was a few litres more than it should be (but not many). However I took a reading after racking and the gravity (at 20degc) was 1.048. This is a whole 13 - 15 points less than it should be.

I know it will probably turn out ok if a little weak and I am not obsessed with OG but I would like to hear some thoughts about what it could have been. I don't think the extra litres could have had such a large effect and like I said the grain looked ok. Did it have something to do with the oats or wheat in the recipe?

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My money would be on oversparging. You said the preboil volume was high. What's the batch size? A few litres is a lot in a 20L batch. I would recommend measuring preboil gravity and volume as a rule, if you take these measurements and know your normal boiloff rate, you can correct most gravity related issues before they become issues.

Do you normally get closer to your target gravity?

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  • Hi, thanks for the answer. Yeah it was a 23l batch. Every brew I did until now was in the ballpark, that's why I started getting lazy with the preboil measurements. My mash and sparge water volumes are calced using www.grainfather.com/brewing . That comes up with around d 32l for the 23l batch
    – dashambles
    Commented Feb 28, 2019 at 23:48
  • Just for your peace of mind, I would suggest you read up a bit on how to do these calcs yourself, if you don't already know, and then compare your results with the grainfather calc. That, coupled with taking the right measurements, should help you figure out where your efficiency went. With a quick calc, at 23L target OG 1.062, you would have been off by almost 7L. Totally possible that half of your efficiency loss is from volume though, and the other half from some other factor, like a high gravity mash.
    – Frazbro
    Commented Mar 1, 2019 at 2:45
  • Thanks I did that now and it's not that complicated. From that I think I just made a stupid mistake: I did a 23l batch where the recipe is for 19l.
    – dashambles
    Commented Mar 1, 2019 at 7:01

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