Why is my bechamel/white sauce lumpy?

I made a bechamel sauce for the first time in years and I couldn't get the lumps completely out, even after resorting to using an electric whisk. Eventually had to strain it.
Any tips on how to make it - without lumps.
Thanks
Answers:
The only time i've had sauces go lumpy is when i rush them. you have to make sure you make a roux with the flour and butter and make sure its a smoothe paste before adding the milk.
keep whisking as it comes to the boil
Béchamel Sauce

Béchamel is very important in the making of lasagne and sformati. It can also be introduced into a rich meat sauce to give it a creamy, velvety texture.

This recipe should yeild a fairly soft sauce. If it is too thick add more milk, or water. If you think you have some lumps in it there is no reason to get depressed. Pass it through a fine sieve and everything will be all right.

Makes - 2 L (8 cups), Preparation time - 30 minutes.

Ingredients


150 g (5 oz) unsalted butter
100 g (3½ oz) plain (all-purpose) flour
1.5 L (6 cups) hot milk
freshly grated nutmeg (optional)

Method


Melt the butter and mix with the flour. Cook a little but without browning. Allow to cool and stir in the milk, bit by bit, mixing with a wooden spoon. Initially the mixture will be like a gluggy lump but as you add the milk it will break down more and more. Cook it gently for 20 minutes or more, taking care that it does not stick to the bottom of the pan. Add nutmeg to taste. Do not worry about flavouring the béchamel with onions - it will be incorporated with very strongly flavoured foods.

When using for sformati, the béchamel needs to be of a firm consistency, and the nutmeg should be omitted.
Make a smooth roux by heating the flour and butter (or fat of some sort) make sure all the lumps are out of that before adding any milk - I use a tiny whisk. Then add the milk SLOWLY, stirring well all the time so no big lumps form, keep adding and stirring till the sauce is the consistency you want.
it was lumpy because the flour cooked before the liquid.

use a hand whisk (not an electric one) from the start - as soon as you start putting the milk into the roux (flour/butter mixture). tedious, but always effective.
I don't care what the recipe says, do not add the liquid all at once. I sort of drizzle it in, whisk, drizzle some more, whisk a lot, repeat. :)
I use full-cream milk, add pepper and salt, mix about 2 heaped teaspoons of Maizena [ corn-flour ] with a bit of cold water, heat the milk then pour in the corn-flour and stir with one of those wiry egg-whisks or a spoon, as the milk heats up it will start thickening just stir faster and never leave it alone until you have finished with the sauce. I find the quickest way to make a sauce is in the microwave stir maizena into milk stick in microwave and as it starts boiling up take out and stir well, do that until the sauce is smooth, never leave it alone.:))))
Sieve the flour first, and keep stirring when heating it.
once milk has been added, never stop stirring!! xx
follow this recipe and you cant go wrong. my mum taught me it and everytime i make it it always turns out perfect!
1. put 50g of butter and 50g of plain flour in a saucepan
2. whisk it together until it becomes a creamy mixture like when you cream butter and sugar
3. add 500ml of milk in the saucepan slowly and keep mixing
4. keep doing this until you have added all of the milk
5. put about 75g of grated cheddar cheese in to make it extra tasty and keep mixing.
5. take of the heat and add nutmeg for some flavour

hope the next time you make it it turns out well without lumps! i think that if you cream the flour and butter together well and then add the milk slowly it wil turn out fine!

another tip is to have the butter at room temperature when you do it, so it is easier to cream togther!

good luck! :)
Usually because it's too hot, I think. Do it slowly, with continued stirring.
By the way, I always make mine in the microwave oven. Works much better.
I learned how to make this sauce in France and I still recite the golden rule to myself. If you add cold milk, you add it all at once to the roux mixture. If you add hot milk, you add it gradually. I always use a hand whisk when making it. Eliminate those lumps from the start!
Start with cold liquid.
You added the milk too quickly
It helps if you add hot liquid to the roux in small amounts whisking every time. Allow the flour to cook out on a low heat for about 40 mins.
Melt your butter then add your flour a little at a time. Make sure the flour is completely lump free when you add it to the melted butter by using a whisk. Then after each introduction of liquid whisk again. By starting with a lump free "rue" your bechamel sauce will be lump free too. This is true for any kind of sauce or gravy.
Add milk slowly whilst whisking but don't bring to the boil mixture.
I think it helps to get your smooth paste with the flour and butter first, and add room temperature or hot milk gradually, and to keep stirring. I recently tried a recipe, though, where you put everything in at once (equal quantities of flour and butter, plus milk and nutmeg), then continually whisk over low heat til it gets to boiling point. To my surprise, it worked.
You're heat might have been too high and it boiled faster then you could whip it.

I've never had issues with mine, but straining it was a nice recovery. I would suggest turning the heat down some when it starts to boil and then whisking the heck out of it lol
seive the flour into the rhu, but then you have to constantly whisk it too.