Strange astringent flavour?

Hi all,

I've been brewing for a long while and have only recently come across a strange problem with my Weissbier, and am wondering if anyone can help me troubleshoot it?

Recently, over the past few months, the aftertaste has gone a bit bitter / astringent.

The grist bill has never changed, it's the same one I've made for 4 years now:

56% Weyermann Wheat Malt
34% Weyermann Pilsner Malt
13% Weyermann Cara-Munich Type 1

60g of hops boiled for 55 minutes

I use a custom built 50 litre RIMS 3 vessel system (HLT, M/LT and a Kettle). The system has had no changes made to it.

Fermentation is in 60 litre Speidel plastic fermenters (these are replaced on a regular basis).

The only possible changes would be:

1. Source of Hersbrucker hops dried up, so have moved to Hallertauer hops, date on package is 2013, but they have always been kept in a refrigerator. Colour of pellets is bright green, so no visible signs of oxidation.

2. Possible that the temp of the sparge water is higher (180°F instead of 170°C)

3. Change in yeast from Wyeast 3333 to Wyeast 3638.


A year ago, we did have a few infected batches (due to rotting vegetables in the room next door). But that produced a beer that was undrinkable.


Anyone have any ideas?

Thanks,
Hector

Most likely #2. The three sources of tannins are mash ph above 5.5, Grain temp exceeding 170, and over sparging to the point that your runnings drop below 1.010.

I'd check your ph during the mash and have a small sack of calcium carbonate at the ready.

I recently had pH issues with my brews that I tracked down to my variably sourced city water. The water company changes the mix seasonally between well and reservoir water. I went to adjust my mash water pH with my standard amount of lactic and found it was still around 6.5. I ended up adding twice the usual amount to get it in the correct range. Did you check your sparge pH? If the temp and pH are both high, you will get tannins.

Thanks all.

I will try all of your recommendations.

Cheers!
Hector